Question

The side of a rectangle are in the ratio 5 : 4. If its perimeter is 72 cm, then its length is

(a) 40 cm
(b) 20 cm
(c) 30 cm
(d) 60 cm

Answer 1

(b) 20 cm
Let the sides of the rectangle be 5x and 4x. (Since, they are in the ratio 5 : 4)
Now, perimeter of rectangle = 2 (Length + Breadth)
72 = 2 (5x + 4x)
72 = 2 $\times$ 9x
72 = 18x
x = $\frac{72}{18}$ = 4
Thus, the length of the rectangle = 5x = 5 $\times$ 4 = 20 cm