Measurements and Geometry

Similarity and Enlargement - Properties of similar figures
Similarity and Enlargement - Centre of enlargement and linear scale factor

By the end of the lesson, the learner should be able to:

- Identify properties of similar figures
- Compare corresponding sides and angles of similar figures
- Relate similarity to real life objects like photographs and maps

- Collect objects from the environment and sort similar objects together
- Measure corresponding sides of similar triangles and determine ratios
- Measure corresponding angles of similar figures
- Discuss reasons why objects are considered similar

How do we identify similar figures in our environment?

- Mentor Essential Mathematics pg. 31
- Similar objects (containers, shapes)
- Rulers and protractors
- Digital resources
- Mentor Essential Mathematics pg. 37
- Plain paper
- Rulers
- Pencils

- Observation - Oral questions - Written assignments

Measurements and Geometry

Similarity and Enlargement - Linear scale factor
Similarity and Enlargement - Drawing images under enlargement

By the end of the lesson, the learner should be able to:

- Determine the linear scale factor of similar figures
- Calculate linear scale factor from given measurements
- Apply linear scale factor concepts to map reading and architectural drawings

- Measure distances from centre of enlargement to object and image
- Calculate ratio of image distance to object distance
- Work out linear scale factors for different figures
- Discuss applications of scale factors

What is the relationship between object and image distances?

- Mentor Essential Mathematics pg. 38
- Rulers
- Graph paper
- Calculators
- Mentor Essential Mathematics pg. 40
- Geometrical instruments

- Observation - Oral questions - Written tests

Measurements and Geometry

Similarity and Enlargement - Drawing images on Cartesian plane
Similarity and Enlargement - Area scale factor

By the end of the lesson, the learner should be able to:

- Draw images on Cartesian plane given scale factor and centre
- Plot coordinates of image points
- Apply enlargement skills to graphic design and scaling images

- Plot objects on Cartesian plane
- Calculate image coordinates using scale factor
- Draw images under enlargement with different centres
- Verify accuracy of constructions

How do we enlarge figures on the Cartesian plane?

- Mentor Essential Mathematics pg. 41
- Graph paper
- Rulers
- Pencils
- Mentor Essential Mathematics pg. 42
- Calculators
- Rulers

- Observation - Practical work - Written tests

Measurements and Geometry

Similarity and Enlargement - Area scale factor calculations

By the end of the lesson, the learner should be able to:

- Calculate area scale factor from given measurements
- Apply area scale factor formula
- Use area scale factor in calculating painting and carpeting costs

- Work out area scale factors for various similar figures
- Solve problems involving area scale factor
- Apply area scale factor to real-life scenarios
- Share solutions with peers

How is area scale factor applied in real life?

- Mentor Essential Mathematics pg. 44
- Calculators
- Rulers
- Digital resources

- Observation - Oral questions - Written tests

Measurements and Geometry

Similarity and Enlargement - Volume scale factor

By the end of the lesson, the learner should be able to:

- Determine the volume scale factor of similar objects
- Calculate volumes of similar solids
- Apply volume scale factor to container sizing and packaging

- Collect similar containers of different sizes
- Calculate volumes of similar cuboids
- Determine ratio of volumes
- Establish relationship between linear and volume scale factors

What is the relationship between linear scale factor and volume scale factor?

- Mentor Essential Mathematics pg. 43
- Similar containers
- Rulers
- Calculators

- Observation - Oral questions - Written assignments

Measurements and Geometry

Similarity and Enlargement - Relating linear, area and volume scale factors

By the end of the lesson, the learner should be able to:

- Relate linear scale factor to area and volume scale factors
- Convert between different scale factors
- Apply scale factor relationships to model making and engineering

- Make similar cylinders of different sizes
- Calculate ratios of heights, areas, and volumes
- Compare the three ratios and establish relationships
- Solve problems involving all three scale factors

How are the three scale factors related?

- Mentor Essential Mathematics pg. 45
- Manila paper
- Calculators
- Scissors

- Observation - Oral questions - Written tests

Measurements and Geometry

Similarity and Enlargement - Application to area

By the end of the lesson, the learner should be able to:

- Apply linear scale factor to find areas of similar figures
- Solve problems on area using scale factors
- Connect similarity concepts to architectural blueprints and scale models

- Calculate areas of similar figures using scale factors
- Solve word problems involving area scale factor
- Use digital devices to explore applications
- Present solutions to peers

How do we apply area scale factor to solve problems?

- Mentor Essential Mathematics pg. 46
- Calculators
- Digital resources
- Reference books

- Observation - Oral questions - Written assignments

Measurements and Geometry

Similarity and Enlargement - Application to volume
Reflection - Lines of symmetry in plane figures

By the end of the lesson, the learner should be able to:

- Apply linear scale factor to find volumes of similar objects
- Solve problems on volume using scale factors
- Use similarity in estimating storage capacities and tank volumes

- Calculate volumes of similar solids using scale factors
- Solve word problems involving volume scale factor
- Complete project on making similar containers
- Document processes and take pictures

How do we apply volume scale factor to solve problems?

- Mentor Essential Mathematics pg. 47
- Calculators
- Manila paper
- Locally available materials
- Mentor Essential Mathematics pg. 50
- Paper cut-outs
- Scissors
- Various 2D objects

- Observation - Project assessment - Written tests

Measurements and Geometry

Reflection - Lines of symmetry in regular polygons

By the end of the lesson, the learner should be able to:

- Determine lines of symmetry in regular polygons
- State that regular polygons have lines of symmetry equal to number of sides
- Connect symmetry to design patterns in fabric and architecture

- Draw regular polygons and identify lines of symmetry
- Trace diagrams and draw lines of symmetry
- State number of lines of symmetry for various alphabets
- Discuss patterns observed

What is the relationship between sides and lines of symmetry in regular polygons?

- Mentor Essential Mathematics pg. 52
- Rulers
- Protractors
- Plain paper

- Observation - Oral questions - Written tests

Measurements and Geometry

Reflection - Properties of reflection
Reflection - Drawing images given object and mirror line

By the end of the lesson, the learner should be able to:

- Determine the properties of reflection using objects and images
- Compare distances of object and image from mirror line
- Relate reflection properties to how mirrors work in daily life

- Observe triangle ABC and its image A'B'C' after reflection
- Compare sizes and shapes of object and image
- Measure and compare distances from mirror line
- Stand at different distances from plane mirror and observe

What are the properties of reflection?

- Mentor Essential Mathematics pg. 53
- Plane mirrors
- Rulers
- Plain paper
- Mentor Essential Mathematics pg. 54
- Plain paper
- Set squares

- Observation - Oral questions - Written assignments

Measurements and Geometry

Reflection - Reflection along x = 0
Reflection - Reflection along y = 0

By the end of the lesson, the learner should be able to:

- Draw an image after reflection along the line x = 0
- Determine coordinates of image points when reflected along y-axis
- Connect reflection to creating symmetric designs and logos

- Plot triangles on Cartesian plane
- Reflect points along line x = 0
- Record coordinates of object and image points
- Observe pattern in coordinates after reflection

What happens to coordinates when reflecting along x = 0?

- Mentor Essential Mathematics pg. 56
- Graph paper
- Rulers
- Pencils
- Mentor Essential Mathematics pg. 58
- Calculators

- Observation - Oral questions - Written assignments

Measurements and Geometry

Reflection - Reflection along y = x
Reflection - Drawing mirror line given object and image on plane surface

By the end of the lesson, the learner should be able to:

- Draw an image after reflection along the line y = x
- Determine coordinates of image points when reflected along y = x
- Use reflection in creating tessellations and artistic patterns

- Plot triangles on Cartesian plane
- Draw line y = x and reflect points
- Record and compare coordinates
- Establish the rule for reflection along y = x

What happens to coordinates when reflecting along y = x?

- Mentor Essential Mathematics pg. 57
- Graph paper
- Rulers
- Pencils
- Mentor Essential Mathematics pg. 60
- Plain paper
- Compasses

- Observation - Practical work - Written assignments

Measurements and Geometry

Reflection - Drawing mirror line on Cartesian plane

By the end of the lesson, the learner should be able to:

- Draw the mirror line given an object and its image on Cartesian plane
- Identify the equation of the mirror line
- Connect mirror line concepts to coordinate geometry applications

- Plot objects and their images on Cartesian plane
- Join corresponding vertices
- Construct perpendicular bisectors
- Determine equation of mirror line

How do we determine the equation of a mirror line?

- Mentor Essential Mathematics pg. 61
- Graph paper
- Rulers
- Compasses

- Observation - Oral questions - Written assignments

Measurements and Geometry

Reflection - Application in real life situations

By the end of the lesson, the learner should be able to:

- Apply reflection in real-life situations
- Solve problems involving reflection
- Use reflection concepts in understanding driving mirrors and road safety

- Discuss uses of reflection in real life
- Solve problems involving town layouts and architectural designs
- Work with peers to apply reflection to practical situations
- Present findings to class

How is reflection used in day-to-day activities?

- Mentor Essential Mathematics pg. 63
- Graph paper
- Rulers
- Digital resources

- Observation - Oral questions - Written tests

Measurements and Geometry

Trigonometry - Identifying sides of a right-angled triangle
Trigonometry - Tangent ratio

By the end of the lesson, the learner should be able to:

- Identify the sides of a right-angled triangle in relation to a particular angle
- Name the hypotenuse, opposite and adjacent sides
- Recognize right-angled triangles in structures like ladders, ramps and roofs

- Lean a ladder against classroom wall and identify triangle formed
- Name the type of triangle formed
- Identify hypotenuse, opposite and adjacent sides relative to angle θ
- Discuss real-life examples of right-angled triangles

How do we identify the sides of a right-angled triangle?

- Mentor Essential Mathematics pg. 65
- Ladders
- Protractors
- Rulers
- Mentor Essential Mathematics pg. 67
- Rulers
- Calculators

- Observation - Oral questions - Written assignments

Measurements and Geometry

Trigonometry - Applications of tangent ratio
Trigonometry - Sine ratio

By the end of the lesson, the learner should be able to:

- Apply tangent ratio to solve problems
- Calculate tangent from real-life situations
- Use tangent in determining slopes of ramps and roof pitches

- Calculate tangent of angles formed by ladders and walls
- Work out tangent of angles in roof designs
- Solve problems involving ramps and inclined surfaces
- Share solutions with classmates

How is tangent ratio applied in real life?

- Mentor Essential Mathematics pg. 68
- Calculators
- Rulers
- Reference books
- Mentor Essential Mathematics pg. 69
- Protractors
- Calculators

- Observation - Oral questions - Written assignments

Measurements and Geometry

Trigonometry - Applications of sine ratio
Trigonometry - Cosine ratio

By the end of the lesson, the learner should be able to:

- Apply sine ratio to solve problems
- Calculate sine from real-life situations
- Use sine in determining heights of slides and inclined structures

- Calculate sine of angles formed by ladders and ground
- Work out sine of angles in roof truss designs
- Solve problems involving playground slides
- Present solutions to peers

How is sine ratio applied in real life?

- Mentor Essential Mathematics pg. 71
- Calculators
- Rulers
- Digital resources
- Mentor Essential Mathematics pg. 72
- Protractors
- Calculators

- Observation - Oral questions - Written assignments

Measurements and Geometry

Trigonometry - Applications of cosine ratio

By the end of the lesson, the learner should be able to:

- Apply cosine ratio to solve problems
- Calculate cosine from real-life situations
- Use cosine in determining base distances and horizontal measurements

- Calculate cosine of angles formed by ladders and ground
- Work out cosine of angles in warehouse roof designs
- Solve problems involving ramps and inclined surfaces
- Share solutions with classmates

How is cosine ratio applied in real life?

- Mentor Essential Mathematics pg. 74
- Calculators
- Rulers
- Reference books

- Observation - Oral questions - Written assignments

Measurements and Geometry

Trigonometry - Sines and cosines of complementary angles
Trigonometry - Solving equations involving complementary angles

By the end of the lesson, the learner should be able to:

- Relate sines and cosines of complementary angles
- Use calculator to find sines and cosines of complementary angles
- Apply complementary angle relationships to solving equations

- Discuss meaning of complementary angles
- Use calculator to complete table of sin θ and cos(90°-θ)
- Observe that sin α = cos(90°-α)
- Verify relationship using different angle pairs

What is the relationship between sine and cosine of complementary angles?

- Mentor Essential Mathematics pg. 75
- Scientific calculators
- Reference books
- Digital resources
- Mentor Essential Mathematics pg. 76
- Exercise books
- Reference books

- Observation - Oral questions - Written tests

Measurements and Geometry

Trigonometry - Making a clinometer

By the end of the lesson, the learner should be able to:

- Make a simple clinometer using locally available materials
- Use the clinometer to measure angles
- Apply clinometer skills to measuring heights of buildings and trees

- Gather manila paper, protractor, string and weight
- Trace protractor's curved edge and mark degrees
- Attach straw along straight edge
- Tie string with weight at centre point

How do we make and use a clinometer?

- Mentor Essential Mathematics pg. 77
- Manila paper
- Blackboard protractor
- String and weight

- Observation - Practical work - Oral questions

Measurements and Geometry

Trigonometry - Angle of elevation

By the end of the lesson, the learner should be able to:

- Apply trigonometric ratios to angles of elevation
- Calculate heights using angles of elevation
- Use angle of elevation in determining heights of flagpoles, trees and buildings

- Use clinometer to measure angle of elevation of tall objects
- Measure horizontal distance from object
- Apply trigonometric ratios to calculate heights
- Compare calculated heights with actual measurements

How do we use angles of elevation to find heights?

- Mentor Essential Mathematics pg. 79
- Clinometers
- Tape measures
- Calculators

- Observation - Practical work - Written tests

Measurements and Geometry

Trigonometry - Problems on angle of elevation

By the end of the lesson, the learner should be able to:

- Solve problems involving angles of elevation
- Apply trigonometric ratios to real-life situations
- Calculate heights of towers, monuments and tall structures

- Draw sketches from word problems
- Identify given information and required values
- Apply appropriate trigonometric ratios
- Calculate heights and distances

How do we solve problems on angles of elevation?

- Mentor Essential Mathematics pg. 80
- Calculators
- Rulers
- Exercise books

- Observation - Oral questions - Written assignments

Measurements and Geometry

Trigonometry - Problems on angle of elevation

By the end of the lesson, the learner should be able to:

- Solve problems involving angles of elevation
- Apply trigonometric ratios to real-life situations
- Calculate heights of towers, monuments and tall structures

- Draw sketches from word problems
- Identify given information and required values
- Apply appropriate trigonometric ratios
- Calculate heights and distances

How do we solve problems on angles of elevation?

- Mentor Essential Mathematics pg. 80
- Calculators
- Rulers
- Exercise books

- Observation - Oral questions - Written assignments

Measurements and Geometry

Trigonometry - Angle of depression

By the end of the lesson, the learner should be able to:

- Apply trigonometric ratios to angles of depression
- Calculate distances using angles of depression
- Use angle of depression in aviation and marine navigation

- Discuss meaning of angle of depression
- Draw diagrams showing angles of depression
- Apply trigonometric ratios to find distances
- Solve problems involving observers on cliffs and buildings

How do we use angles of depression to find distances?

- Mentor Essential Mathematics pg. 80
- Calculators
- Rulers
- Digital resources

- Observation - Oral questions - Written tests

Measurements and Geometry

Trigonometry - Application in real life situations
Area of Polygons - Area of triangle given two sides and an included angle

By the end of the lesson, the learner should be able to:

- Solve combined problems on angles of elevation and depression
- Apply trigonometry to various real-life scenarios
- Use trigonometry in determining distances between ships, aircraft heights and building measurements

- Solve problems involving two ships viewed from cliff
- Calculate distances and heights in combined scenarios
- Use digital resources to explore more applications
- Present solutions to class

How is trigonometry used in real life?

- Mentor Essential Mathematics pg. 81
- Calculators
- Digital resources
- Reference books
- Mentor Essential Mathematics pg. 84
- Rulers
- Protractors
- Calculators

- Observation - Oral questions - Written assignments

Measurements and Geometry

Area of Polygons - Problems on area of triangle
Area of Polygons - Heron's Formula

By the end of the lesson, the learner should be able to:

- Solve problems on area of triangles using ½ab sin C
- Find unknown sides or angles given the area
- Apply triangle area calculations to land surveying and construction

- Work out areas of triangular kitchen gardens
- Calculate areas of equilateral triangular seedbeds
- Solve for unknown angles when area is given
- Discuss applications in real life

How do we solve problems involving area of triangles?

- Mentor Essential Mathematics pg. 85
- Calculators
- Rulers
- Exercise books
- Mentor Essential Mathematics pg. 86
- Scientific calculators

- Observation - Oral questions - Written tests

Measurements and Geometry

Area of Polygons - Problems using Heron's Formula

By the end of the lesson, the learner should be able to:

- Solve problems on area of triangles using Heron's Formula
- Calculate areas of triangles with all three sides given
- Apply Heron's formula to triangular parks, gardens and stool tops

- Calculate areas of triangular cut-outs
- Work out areas of traditional stool tops
- Solve problems on triangular vegetable gardens
- Present solutions to peers

How is Heron's Formula applied in real life?

- Mentor Essential Mathematics pg. 87
- Calculators
- Exercise books
- Reference books

- Observation - Oral questions - Written tests

Measurements and Geometry

Area of Polygons - Area of a rhombus
Area of Polygons - Area of rhombus given side and angle

By the end of the lesson, the learner should be able to:

- Determine the area of a rhombus given the diagonals
- Apply the formula Area = ½ × d₁ × d₂
- Calculate areas of rhombus-shaped tiles, kites and floor patterns

- Draw rhombus and measure diagonals
- Calculate areas of triangles formed by diagonals
- Add areas to get total area of rhombus
- Verify using formula ½ × d₁ × d₂

How do we find the area of a rhombus?

- Mentor Essential Mathematics pg. 88
- Rulers
- Protractors
- Calculators
- Mentor Essential Mathematics pg. 89
- Calculators
- Protractors

- Observation - Oral questions - Written assignments

Measurements and Geometry

Area of Polygons - Area of a parallelogram
Area of Polygons - Area of parallelogram using ab sin θ

By the end of the lesson, the learner should be able to:

- Determine the area of a parallelogram
- Apply the formula Area = base × perpendicular height
- Calculate areas of parallelogram-shaped solar panels and floor plans

- Draw parallelogram with given dimensions
- Calculate perpendicular height using trigonometry
- Apply formula: base × perpendicular height
- Work out areas of various parallelograms

How do we find the area of a parallelogram?

- Mentor Essential Mathematics pg. 92
- Rulers
- Protractors
- Calculators
- Mentor Essential Mathematics pg. 94
- Calculators
- Exercise books

- Observation - Oral questions - Written assignments

Measurements and Geometry

Area of Polygons - Area of a regular pentagon

By the end of the lesson, the learner should be able to:

- Determine the area of a regular pentagon
- Divide pentagon into triangles and calculate total area
- Apply pentagon area to flower bed designs and pizza box lids

- Draw regular pentagon and divide into 5 triangles
- Measure radius from centre to vertex
- Calculate area of one triangle
- Multiply by 5 to get total area

How do we find the area of a regular pentagon?

- Mentor Essential Mathematics pg. 95
- Rulers
- Protractors
- Calculators

- Observation - Oral questions - Written assignments

Measurements and Geometry

Area of Polygons - Problems on area of pentagon

By the end of the lesson, the learner should be able to:

- Solve problems on area of regular pentagons
- Calculate areas of pentagon-shaped objects
- Apply pentagon area to trampoline covers and decorative designs

- Calculate area of pentagon-shaped flower beds
- Work out area of pizza box lids
- Solve problems involving pentagon-shaped objects
- Present solutions to class

How is area of pentagon applied in real life?

- Mentor Essential Mathematics pg. 97
- Calculators
- Exercise books
- Digital resources

- Observation - Oral questions - Written tests

Measurements and Geometry

Area of Polygons - Area of a regular hexagon

By the end of the lesson, the learner should be able to:

- Determine the area of a regular hexagon
- Divide hexagon into 6 triangles and calculate total area
- Apply hexagon area to floor tiling and road sign designs

- Draw regular hexagon and divide into 6 triangles
- Measure radius from centre to vertex
- Calculate area of one triangle
- Multiply by 6 to get total area

How do we find the area of a regular hexagon?

- Mentor Essential Mathematics pg. 96
- Rulers
- Protractors
- Calculators

- Observation - Oral questions - Written assignments

Measurements and Geometry

Area of Polygons - Application in real life situations

By the end of the lesson, the learner should be able to:

- Apply areas of polygons in real-life situations
- Solve combined problems on areas of polygons
- Use polygon areas in calculating material costs and backyard coverage

- Calculate areas of hexagonal tile sections
- Work out total area of backyards covered with hexagonal blocks
- Determine cost of materials for polygon-shaped items
- Discuss applications in day-to-day life

How are areas of polygons useful in real life?

- Mentor Essential Mathematics pg. 98
- Calculators
- Digital resources
- Reference books

- Observation - Oral questions - Written tests

Measurements and Geometry

Area of a Part of a Circle - Area of a sector
Area of a Part of a Circle - Problems on area of sector

By the end of the lesson, the learner should be able to:

- Determine the area of a sector of a circle
- Apply the formula Area = θ/360 × πr²
- Calculate areas of hand-fans, sprinkler coverage and cake toppings

- Draw circle and mark sector AOB
- Measure radius and angle subtended at centre
- Apply formula θ/360 × πr²
- Share findings with classmates

How do we find the area of a sector?

- Mentor Essential Mathematics pg. 101
- Compasses
- Protractors
- Calculators
- Mentor Essential Mathematics pg. 102
- Calculators
- Rulers
- Exercise books

- Observation - Oral questions - Written assignments

Measurements and Geometry

Area of a Part of a Circle - Area of a segment
Area of a Part of a Circle - Problems on area of segment

By the end of the lesson, the learner should be able to:

- Determine the area of a segment of a circle
- Apply the formula: Area of sector - Area of triangle
- Calculate areas of parking lots, decorations and glass windows

- Draw circle with sector and identify segment
- Calculate area of sector using θ/360 × πr²
- Calculate area of triangle using ½r² sin θ
- Subtract to get area of segment

How do we find the area of a segment?

- Mentor Essential Mathematics pg. 103
- Compasses
- Protractors
- Calculators
- Mentor Essential Mathematics pg. 105
- Calculators
- Exercise books
- Reference books

- Observation - Oral questions - Written assignments

Measurements and Geometry

Area of a Part of a Circle - Area swept by gate

By the end of the lesson, the learner should be able to:

- Apply area of sector to find area swept by rotating objects
- Calculate area covered by opening gates and doors
- Use sector area in clock hand problems and fan blade designs

- Observe area covered by gate when it opens
- Measure angle of rotation and length of gate
- Calculate area swept using sector formula
- Discuss other applications

How do we calculate area swept by rotating objects?

- Mentor Essential Mathematics pg. 107
- Tape measures
- Protractors
- Calculators

- Observation - Practical work - Written assignments

Measurements and Geometry

Area of a Part of a Circle - Problems on curved paths and decorations
Area of a Part of a Circle - Clock and sprinkler problems

By the end of the lesson, the learner should be able to:

- Calculate areas of curved paths and decorations
- Solve problems on sector and segment areas
- Apply concepts to fan blade designs and table cloth decorations

- Calculate area of curved paths in school compound
- Work out area of decorations on table cloths
- Solve problems on fanning papers
- Present solutions to class

How are areas of parts of circles applied in design?

- Mentor Essential Mathematics pg. 108
- Calculators
- Rulers
- Digital resources
- Mentor Essential Mathematics pg. 110
- Clocks
- Reference books

- Observation - Oral questions - Written tests

Measurements and Geometry

Area of a Part of a Circle - Combined problems
Surface Area of Solids - Nets of cones

By the end of the lesson, the learner should be able to:

- Solve combined problems on sectors and segments
- Apply area of parts of circles in various contexts
- Use concepts in calculating metal sheet areas and flower garden segments

- Calculate area of metal sheet in segment shape
- Work out area of flower segments in circular gardens
- Solve problems on staffroom doors and gates
- Review all concepts on area of parts of circles

Where do we use area of part of a circle in real life?

- Mentor Essential Mathematics pg. 111
- Calculators
- Exercise books
- Digital resources
- Mentor Essential Mathematics pg. 112
- Manila paper
- Scissors
- Cone-shaped objects

- Observation - Oral questions - Written tests

Measurements and Geometry

Surface Area of Solids - Surface area of a cone from its net
Surface Area of Solids - Surface area of cone using formula

By the end of the lesson, the learner should be able to:

- Determine surface area of cones from nets
- Calculate area of sector and circular base
- Apply cone surface area to calculating material for making party hats and funnels

- Measure angle, radius of sector and radius of circular base
- Calculate area of sector using θ/360 × πr²
- Calculate area of circular base using πr²
- Add to get total surface area

How do we find the surface area of a cone from its net?

- Mentor Essential Mathematics pg. 113
- Cone nets
- Protractors
- Calculators
- Mentor Essential Mathematics pg. 114
- Calculators
- Exercise books
- Reference books

- Observation - Oral questions - Written tests

Measurements and Geometry

Surface Area of Solids - Nets of pyramids

By the end of the lesson, the learner should be able to:

- Identify nets of square and rectangular-based pyramids
- Draw nets of pyramids
- Connect pyramid shapes to monuments, roof structures and tent designs

- Make models of square and rectangular-based pyramids
- Cut and open pyramids along edges to get nets
- Measure edges and slant heights
- Identify base and triangular faces in nets

What shapes make up the net of a pyramid?

- Mentor Essential Mathematics pg. 115
- Manila paper
- Scissors
- Rulers

- Observation - Practical work - Written tests

Measurements and Geometry

Surface Area of Solids - Surface area of square-based pyramid
Surface Area of Solids - Surface area of rectangular-based pyramid

By the end of the lesson, the learner should be able to:

- Determine surface area of square-based pyramids from nets
- Calculate area of square base and triangular faces
- Apply to gift box designs, glass covers for skylights and decorative items

- Sketch net of square-based pyramid
- Calculate area of square base
- Calculate area of four identical triangular faces
- Add to get total surface area

How do we find surface area of a square-based pyramid?

- Mentor Essential Mathematics pg. 116
- Graph paper
- Calculators
- Rulers
- Mentor Essential Mathematics pg. 117

- Observation - Oral questions - Written assignments

Measurements and Geometry

Surface Area of Solids - Surface area of a sphere
Surface Area of Solids - Surface area of a hemisphere

By the end of the lesson, the learner should be able to:

- Calculate the surface area of a sphere
- Apply the formula 4πr²
- Use sphere surface area in calculating material for balls, globes and decorative spheres

- Collect spherical objects (soccer balls, marbles, oranges)
- Estimate and record radius of each object
- Calculate surface area using formula 4πr²
- Share work with other groups

How do we find the surface area of a sphere?

- Mentor Essential Mathematics pg. 120
- Spherical objects
- Rulers
- Calculators
- Mentor Essential Mathematics pg. 121
- Oranges
- Knives

- Observation - Oral questions - Written assignments

Measurements and Geometry

Surface Area of Solids - Surface area of frustum of a cone

By the end of the lesson, the learner should be able to:

- Determine surface area of frustum of a cone
- Identify top radius, bottom radius and slant height
- Apply frustum surface area to bucket designs and lampshade construction

- Make model of cone and cut parallel to base to form frustum
- Identify top radius (r), bottom radius (R) and slant height (L)
- Calculate lateral surface area: πL(R + r)
- Discuss formula for total surface area

How do we find surface area of a frustum of a cone?

- Mentor Essential Mathematics pg. 122
- Manila paper
- Scissors
- Calculators

- Observation - Oral questions - Written assignments

Measurements and Geometry

Surface Area of Solids - Problems on frustum of a cone

By the end of the lesson, the learner should be able to:

- Solve problems on surface area of frustums of cones
- Calculate surface areas of open and closed frustums
- Apply to coffee cups, loudspeaker diaphragms and chemical storage buckets

- Calculate total surface area: πL(R+r) + πR² + πr²
- Work out surface area of open-top coffee cups
- Calculate curved surface area of loudspeaker diaphragms
- Solve problems on buckets storing chemicals

How do we solve problems on frustum surface area?

- Mentor Essential Mathematics pg. 124
- Calculators
- Exercise books
- Reference books

- Observation - Oral questions - Written tests

Measurements and Geometry

Surface Area of Solids - Surface area of frustum of a pyramid

By the end of the lesson, the learner should be able to:

- Determine surface area of frustum of a square-based pyramid
- Calculate lateral surface area using ½(P₁ + P₂) × L
- Apply to lampshade designs, water tanks and display stands

- Make model of pyramid and cut parallel to base
- Identify top perimeter (P₁), bottom perimeter (P₂) and slant height (L)
- Calculate lateral surface area: ½(P₁ + P₂) × L
- Add areas of top and bottom to get total surface area

How do we find surface area of a frustum of a pyramid?

- Mentor Essential Mathematics pg. 125
- Manila paper
- Scissors
- Calculators

- Observation - Practical work - Written assignments

Measurements and Geometry

Surface Area of Solids - Problems on frustum of a pyramid

By the end of the lesson, the learner should be able to:

- Solve problems on surface area of frustums of pyramids
- Calculate surface area of rectangular-based pyramid frustums
- Apply to hollow lampshades, counter designs, statue stands and open water tanks

- Calculate areas of trapezoidal faces for rectangular-based frustums
- Work out surface area of hollow lampshades (lateral only)
- Solve problems on counters and statue stands
- Determine material needed for multiple lampshades

How are frustums of pyramids used in real life?

- Mentor Essential Mathematics pg. 127
- Calculators
- Exercise books
- Digital resources

- Observation - Oral questions - Written tests

Measurements and Geometry

Volume and Capacity - Volume of a cone
Volume and Capacity - Problems on volume of cones

By the end of the lesson, the learner should be able to:

- Determine the volume of a cone
- Apply the formula V = ⅓πr²h
- Relate cone volume to measuring ingredients and ice cream scoops

- Make models of cone and cylinder with equal base radius and height
- Fill cone with sand and empty into cylinder
- Count number of cones needed to fill cylinder
- Establish relationship between cone and cylinder volumes

What is the relationship between volume of a cone and cylinder?

- Mentor Essential Mathematics pg. 132
- Manila paper
- Sand
- Calculators
- Mentor Essential Mathematics pg. 133
- Calculators
- Exercise books
- Reference books

- Observation - Oral questions - Written assignments

Measurements and Geometry

Volume and Capacity - Volume of cone given slant height
Volume and Capacity - Volume of a pyramid

By the end of the lesson, the learner should be able to:

- Calculate volume of cone given slant height and radius
- Use Pythagoras theorem to find vertical height
- Apply to cone-shaped ornaments and decorative items

- Draw cone with slant height and radius labelled
- Apply Pythagorean relationship to find vertical height
- Calculate volume using V = ⅓πr²h
- Solve problems involving slant heights

How do we find volume when slant height is given?

- Mentor Essential Mathematics pg. 134
- Calculators
- Rulers
- Exercise books
- Mentor Essential Mathematics pg. 135
- Pyramid models
- Calculators

- Observation - Oral questions - Written assignments

Measurements and Geometry

Volume and Capacity - Problems on volume of pyramids

By the end of the lesson, the learner should be able to:

- Solve problems on volume of pyramids
- Calculate capacity of pyramid-shaped containers
- Apply pyramid volume to water tanks and yoghurt packaging boxes

- Calculate volume of underground water tanks
- Work out capacity of pyramid-shaped gift boxes
- Determine dimensions when volume is given
- Share solutions with peers

How is pyramid volume applied in real life?

- Mentor Essential Mathematics pg. 136
- Calculators
- Exercise books
- Reference books

- Observation - Oral questions - Written assignments