According to the question,l/[2(l + b)] = 5/18? 10l + 10b = 18l = 10b? l/b = 10/8 = 5/4? l : b = 5 : 4Hence, ratio of length and breadth of a rectangle is 5 : 4
Original area = (22/7) x 9 x 9 cm2New area = (22/7) x 7 x 7 cm2? Decrease = 22/7 x [(9)2 -(7)2] cm2=(22/7) x 16 x 2 cm2Decrease percent = [(22/7 x 16 x 2) /( 7/22 x 9 x 9)] x 100 %= 39.5 %