Question

the length of rectangle is (a-b)cm and breadth is (a+b)cm if b=(28-2a) where a is square of 5 find area of rectangle

Answer 1

Let the rectangle be of length, L, and breadth, B.

Perimeter =2(L+B).

Perimeter : breadth or 2(L+B):B:: 5:1, or

5B =2(L+B) = 2L+2B, or

3B = 2L, or B =(2/3)L …(1). But

LB = 216 …(2), or

L*(2/3)L = 216, or

2L^2 = 216*3, or

L^2 = 108*3 = 324, So L = 18 cm and B = 12 cm.

Answer 2

the area of rectangle is 1316 cm^2