Mr. Rahid fenced a rectangular garden on the three sides and used his garage for the fourth side. If he used a total of 240m of fence, what dimentions would give him the maximum area?

Answer 1

2W + L = 240

L=240-2W

A = LW = (240-2W)W =240W -2W^2

take the derivative and set equal to zero

A' = 240-4W = 0

W = 240/4 = 60 feet wide on two sides

L = 240-2W = 120 feet long on the side opposite the garage

Max area = 60x120 = 7,200 square meters