Q4 of 59 Page 63

The ratio of length and breadth of a rectangle is 3 : 1, and its perimeter is 36 cm. Find the length and breadth of the rectangle.

Let l and b be the length and breadth of rectangle.

Given that Length : Breadth = 3:1


Perimeter of rectangle = 36


Let length of rectangle = l = 3x cm


∴ Breadth of the rectangle = b = x cm


Perimeter of rectangle = 2(l + b) = 36 cm


∴ 2(3x + x) = 36


⇒ 2(4x) = 36


⇒ 8x = 36


⇒ x = 36/8 = 4.5


∴ Breadth of rectangle = x = 4.5 cm


Length of rectangle = 3x = 3 × 4.5 = 13.5 cm


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