If the length of a rectangle is increased by 20% and the width is increased by 30%, then by what percent is the area of the rectangle increased?

Answer 1

area with old dimensions: lw
new length = 1.2l
new width = 1.3w
new area = (1.2l)(1.3)w
= (1.2)(1.3) lw = 1.56 lw
increase = 1.56lw - lw = .56 lw

looks like the area increased by 56%

Answer 2

old A = LW
new A = 1.2L * 1.3W = 1.56 LW or a 56% increase