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Sub – Mathematics

Chapter 9 – AREA & PERIMETER

Sub-topic 2: PERIMETER OF SQUARE AND RECTANGLE

The perimeter of a square is the length that its boundary covers. The perimeter of a square is
obtained by adding all the sides together. Here, the concepts about the perimeter of the square,
formula and derivation along with solved example questions are covered.

What is the Perimeter of a Square?
The perimeter of any closed geometrical object is defined as the distance around that object. For a
square, the perimeter is calculated by adding its four sides. We know that all the sides of a square
are equal and hence, its perimeter will be 4 times its side, i.e. 4 × Side.

The formula for Perimeter of a Square

Perimeter of Square (P) = 4 × Side

How perimeter of a square = 4 x side?

The perimeter of the square is defined as the length of the boundary of a square.
The Perimeter of the square formula is given by,

Perimeter = sum of the lengths of 4 sides
= side + side + side + side
= 4 × side
Therefore, the perimeter of Square = 4s units

Where, s = Length of a side of the square
Example: Find the perimeter of a square whose side is 5 cm.

Solution:
Given:
Side, s = 5 cm

The formula to find the perimeter of a square is given by
The perimeter of Square = 4s units
Substitute the value of ‘s’ in the perimeter formula,

P= 4 × 5 cm
P = 20 cm
Therefore, the perimeter of square = 20 cm

Example: Calculate the perimeter of a square having a side of 16 cm.
Solution:

Given,
Side of the square = a = 16 cm