**Plane Shapes**

These include shapes like Rectangles, Squares, Circles, etc.

**Squares**

These have all the sides equal.

**Perimeter of a Square**

This is the total distance round a square. Since all the sides of a square are equal, and it has four sides, if its length is taken to be L, then the perimeter will be;

P = L+ L+ L+ L

P = 4L

Where P = Perimeter, and L = Length

**Example**

If the length of a square is 6cm, calculate its Perimeter.

Solution

L = 6cm

P = 4L

P = 4 X 6

= 24cm

**Classwork**

- Calculate the perimeter of a square of length 10cm
- The perimeter of a square is 36cm. Calculate its length.

**Area of a Square**

The area of a square is given by the formular

A = L^{2}

Where A = Area

L = Length

**Example**

Calculate the area of a square of length 10cm

Solution

L = 10cm

A = L^{2}

A – 10^{2}

A =100cm^{2}

**Classwork**

- Given a square of length 12cm. Calculate its area
- If the area of a square is 625m
^{2}. Find its length.

**Rectangles**

This has the opposites equal.

**Perimeter of a Rectangle**

P = L+ L +B+ B

P = 2L + 2B

**P = 2(L + B)**

**Example**

A rectangle has length 5cm and breadth 7cm. Calculate its perimeter.

Solution

L = 5cm

B = 7cm

**P = 2(L + B)**

P = 2(5 + 7)

P = 2(12)

= 24cm

**Classwork**

- Calculate the perimeter of a rectangle of length 12cm and breadth 15cm.
- A rectangle has perimeter 20cm and length 5cm. Calculate its breadth

**Area of Rectangle**

The area of a rectangle is given by the formular

**A = L x B**

Where A = area

L = length

B = breadth

**Example**

The length of a rectangle is 6m and its breadth is 9m. Calculate its area.

**Solution**

L = 6m

B = 9m

**A = L x B**

A = 6m x 9m

A = 54m^{2}

**Classwork**

The length of a rectangle is 17cm and its breadth is 18cm. Calculate its area

**Circles**

These are round figures. The **Diameter** of a circle is a line that divides it into two equal halves. Half of a diameter is called a **Radius.**

Thus, radius**, r = d/2.**

**Circumference of a Circle**

The Circumference, C of a circle is given by**;**

**C = 2πr**

Where π is a constant taken as 22/7 or 3.142

r = radius

**Example**

The radius of a circle is 14m. Calculate its circumference (take π = 22/7)

**Solution**

r = 14m

**π = 22/7**

**C = 2πr**

C = 2 x 22/7 x 14

C = 88m

**Classwork**

- The radius of a circle is 14/11 cm. Calculate its circumference.
- The circumference of a circle is 10cm. Calculate its radius. (take
**π = 22/7)**

**Area of a Circle**

The area of a circle is given by

**A = πr ^{2}**

Where A – area

π= 22/7

r = radius

**Example**

The radius of a circle is 14m. Calculate its area. (take π = 22/7)

**Solution**

r = 14m

π= 22/7

A = πr^{2}

A = 22/7 x 14^{2}

=22/7 x 196

= 616m^{2}

**Classwork**

The diameter of a circle is 14cm. Calculate its area. (take π = 22/7)

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