The length and breadth of a square are increased by 40% and 30% respectively. The area of a resulting rectangle exceeds the area of the square by?

Let the side of the square = 100 m
So area of square = 100 x 100 = 10000.
New length = 140 m,
New breadth = 130 m
Increase in area = [(140 x 130) - (100 x 100)] m²
= 8200 m²
∴ Required increase percent = (8200/ 10000) x 100 % = 82%