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\\September 30, 2025 9:51 AM Bharat Arora P-9 Reader _________________________ Date: ___________________74

If we denote the length by l and the breadth by b, then
the perimeter of rectangle ABCD = AB + BC + CD + DA

= l + b q+ l + b = (2l + 2b)

= 2(l + b) = 2 × (Length + Breadth)

Thus, the perimeter of a rectangle is two times the sum of the length and breadth
of the rectangle.

example 4: Find the perimeter of rectangle ABCD shown below.

Solution: Length of the rectangle (l) = 6 cm A 6 cm B

Breadth of the rectangle (b) = 3 cm 3 cm
Perimeter of a rectangle = 2 × (l + b) 3 cm

= 2 × (6 cm + 3 cm) D 6 cm C
= 2 × 9 cm = 18 cm

Thus, the perimeter of rectangle ABCD = 18 cm.

Perimeter of a Square

We know that a square has all its sides of equal length. A a B

Perimeter of a square = Sum of the lengths of its four equal sides

= side + side + side + side a a
= 4 × side = 4 × a
D a C
The perimeter of a square is four times the length of its side.

example 5: Find the perimeter of a square of side 5 cm.

Solution: Length of the side of the square = 5 cm A 5 cm B
Perimeter of the square = 4 × side = 4 × 5 cm 5 cm

= 20 cm 5 cm
Thus, the perimeter of the square is 20 cm. D 5 cm C

Perimeter of an irregular ShaPe

How will you find the perimeter of a figure or Logical Thinking

shape if it is not made up of line segments? Fast Check

To find the perimeter of such figures or shapes, we 1. What is the perimeter of
use a string or thread to measure the boundary your Maths notebook?
of the figure. The total length of the string or 2. What is perimeter of the

thread will give the perimeter of the figure. floor of your classroom?

188 Mathematics-4