Question

Area of a rectangle is 51.2 dm square and the sides are in the ratio 5:4 . Find its perimeter

Answer 1

Given area of rectangle = 51.2 dm²

Sides are in the ratio 5:4

Let x be the common factor

Than length = 5x dm

Breadth = 4x dm

Area of rectange = Length * Breadth

51.2 dm² = 5x * 4x dm²

51.2 = 20 x²

2.56 = x²

x = √2.56

So x = 1.6

Length = 5*x = 8 dm

Breadth = 4*x = 4*1.6 = 6.4 dm

Perimeter of rectangle = 2*(Length + Breadth )

Perimeter = 2*(8+6.4) dm

Perimeter = 2*14.4 = 28.8 dm

Answer : 28.8 dm