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\\December 6, 2023 1:01 PM Bharat Arora P-6 Reader _________________________ Date: ___________________74

Perimeter

Ankit jogs every morning. He wants to go around

the park. So, he starts jogging from a tree, and when
he returns to the tree he has jogged the entire path

around in the park.
The length of the entire path shown by
the black line is the perimeter of the park Knowledge Desk

around which Ankit walks. Thus, the length of The word perimeter is driven from the
the boundary of a closed figure is called its Greek word “Perimetros”. “Peri” means

perimeter. “around” and “Metros” means “measure”.
Perimeter of a Polygon

We know that a polygon is closed figure formed by the line segments.
The perimeter of a polygon is the sum of the length of its sides (line segments)

enclosing the figure.

Perimeter of a polygon = Sum of the lengths of its sides

example 1: Find the perimeter of the following closed figure.

(a) 8 m (b) 3 m

5 m 2 m
7 m
5 m 8 m 10 m 2 m
5 m

10 m 15 m

Solution: (a) Perimeter of the given figure
Note
= Sum of the lengths of its sides We always

= 5 m + 8 m + 7 m + 10 m = 30 m write unit of
measurement after
(b) Perimeter of the given figure the result.

= Sum of the lengths of its sides
= 8 m + 3 m + 5 m + 10 m + 2 m + 2 m + 5 m + 15 m

= 50 m

The perimeter of a polygon can also be found using square grid paper.
If the sides of a polygon lie on the grids of a square paper, we count the number

of unit lengths along the boundary of the figure. The total number of unit length
counted is the perimeter of the figure.

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