The ratio between the perimeter and the breadth of a rectangle is 5:1. If the area of the rectangle is 216 sq. cm, what is the length of the rectangle?
18 cm
2(l+b)b=51⇒ 2l + 2b = 5b ⇒ 3b = 2l ⇒ b = 23 l
Then, area = 216 cm2 ⇒ l × b = 216 ⇒ l × 23l = 216 ⇒l2 = 324 ⇒ l = 18 cm.