Chapter -11

Perimeter and Area

Square

Introduction to square

A square is a flat shape with 4 equal sides and every angle is a right angle i.e. 90°.                                          

Special case of square

In the above figure, ABCD is a square.
Here AB = BC = CD = DA
Each interior angle is 90°.
The Perimeter of square is 4 times the side length. Let a be the length of each side of square.
Now, perimeter of square = 4 * a = 4a
Area of square = side length squared
                        = a * a   
                        = a2

Square area, perimeter & diagonal

Area and Perimeter of Square

Square is a quadrilateral, with four equal sides.
Area = Side × Side
Perimeter = 4 × Side

Example

Find the area and perimeter of a square-shaped cardboard whose length is 5 cm

Solution

Area of square = (side)2
= (5)2
= 25 cm2
Perimeter of square = 4 × side
= 4 × 5
= 20 cm