### AREA AND PERIMETER OF PLANE SHAPES LESSON NOTE AND LESSON PLAN FOR PRIMARY, SECONDARY AND HIGH INSTITUTIONS

W.A.L.A: AREA AND PERIMETER OF PLANE SHAPES

**Monday**

Area of rectangles and squares

Resources

Content

The area of any given shape is the measure of the extent of a surface. Area is measured in square units.

The perimeter of any given shape is the sum of the distance of all the lengths of the sides of that shape.

Examples:

Find the area of a rectangle whose length is 6cm and width 4cm.

A rectangle is 10m long and 7m wide. What is the area?

Solution

Area = L X B

= 6cm X 4cm

= 24 cm²

Area = L X B

= 10 m X 7 m

= 70 m²

Area of Square

Area of square = L² or S². where L= length and S = sides

Examples: Calculate the area of these squares with the following sides.

7 cm

9 m

Solution

Area = L²

= 7cm X 7cm

= 49cm²

Area = S²

= 9m X 9m

= 81m²

Pupils should be Able to ;

Find the area rectangles and squares

Begin the lesson by asking the pupils to measure the length and breadth of the squares and rectangles

**Tuesday**

Area of triangle

The formula for finding area of triangle is 1/2 b x h. Where b is base and h is height of the triangle.

Examples : find the area of the following triangles.

Find the area of a triangle with base of 12m and height of 9 m.

Solution

Area = 1/2 bh

= 1/2 X b X h

= 1/2 X 8cm X 6 cm

= 24cm²

Area of Circle

Area = 1/2 bh

= X b X h

= X 12cm X 9 cm

= 54cm 2

Pupils should be Able to

Find the area of triangle

Begin the lesson by asking them to;

identify a triangle

Then tell them to measure the shapes in centimetres and meters.

Wednesday

Perimeter of squares and rectangles

Examples : find the perimeter of these shapes.

A rectangle with length of 8cm and breadth of 5cm.

A square of sides 9m each.

Solution

Perimeter= L+ B + L + B

= 8cm + 5cm + 8cm + 5cm

=26cm

OR Perimeter = 2 ( L+ B )

= 2 ( 8cm + 5cm)

= 2 X 13cm

= 26cm

Perimeter of square = L + L + L + L

= 9m + 9m + 9m +9m

= 36m

OR Perimeter of square= 4 L

= 4 X 9m

= 36m

Pupils should be Able to ;

State the formulae for finding perimeter of rectangle and square

Begin the lesson by measuring the length of the shapes to be used.

Thursday

Perimeter of triangles

EXAMPLES: find the perimeter of the following shapes with sides :6cm 9cm 5m

and 8cm 4m 7m

Solution

Perimeter = 6cm + 9cm + 8cm

= 23cm

Perimeter = 5m + 4m + 7m + 6 m

=22m

Pupils should be Able to ; calculate the perimeter of any given shapes

Begin the lesson by measuring the sides of the various shapes given.

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