Page 2 - LN

 The Perimeter of a Rectangle:
 A rectangle is a closed figure with two pairs of equal opposite sides and each angle is 90°.

 Perimeter of a rectangle = Sum of all sides
= length + breadth + length + breadth
Thus, Perimeter of a rectangle = 2 × (length + breadth)
Example:
The length and breadth of a rectangular swimming pool are 16 and 12 meters respectively .find
the perimeter of the pool.
Solution:
Perimeter of a rectangle = 2 × (length + breadth)
Perimeter of the pool = 2 × (16 + 12)
= 2 × 28
= 56 m.
 Regular Closed Figure

 Figures with equal length of sides and an equal measure of angles are known as Regular Closed

Figures or Regular Polygon.

 Perimeter of Regular Polygon = Number of sides × Length of one side
 Perimeter of Square

 Square is a regular polygon with 4 equal sides.
 Perimeter of square = side + side + side + side
Thus, Perimeter of a square = 4 × length of a side
Example:
Find the perimeter of a square having side length 25 cm.
Solution:
Perimeter of a square = 4 × length of a side
Perimeter of square = 4 × 25
= 100 cm.

 Perimeter of an Equilateral Triangle
An equilateral triangle is a regular polygon with three equal sides and angles.
Perimeter of an equilateral triangle = 3 × length of a side