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

example 2: Find the perimeter of the following figures by counting unit lengths.
(a) (b) (c)

Solution:
(a) 4 5 6 (b) 4 5 6 7 8 (c) 3

3 7 3 9 2 4 5 6
2 8 2 10 1 7
1 9 1 11 10 9 8
12 11 10 16 15 14 13 12
Perimeter of figure = 12 units Perimeter of figure = 16 units Perimeter of figure = 10 units
Perimeter of a triangle

the perimeter of a triangle is the sum of the lengths of its sides. A

In the adjoining figure, ABC is a triangle.
So, the perimeter of the triangle ABC = AB + BC + CA

example 3: In triangle ABC, AB = 5 cm, BC = 3 cm and CA = 6 cm.

Find its perimeter. B C
Solution: The perimeter of the triangle ABC = sum of the lengths A
of its sides = AB + BC + CA

= 5 cm + 3 cm + 6 cm = 14 cm 5 cm 6 cm

Thus, the perimeter of triangle ABC is 14 cm.
B 3 cm C
Perimeter of a rectangle

The perimeter of a rectangle is the sum of the lengths of A 5 cm B
its four sides.
3 cm 3 cm
example: In the adjoining rectangle, the lengths of the
sides are 5 cm, 3 cm, 5 cm and 3 cm respectively. D 5 cm C
The perimeter of the rectangle ABCD = 5 cm + 3 cm +

5 cm + 3 cm = 16 cm.
We know that the lengths of the opposite sides of a rectangle A l B

are equal. In the adjoining rectangle ABCD, AB = DC and AD = BC.
The longer side is called the length and the shorter side is b b
called the breadth of the rectangle. D l C

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