What is the largest area that can be enclosed?

Question

A developer wants to enclose a rectangular lot that boarders a city street for parking. If the developer has 312 feet of fencing and does not fence the side along the street, what is the largest area that can be enclosed?

Answer 1

P = 2w + L = 318 feet

Area = wL= w(318-2w) = 318w -2w^2

A'= 318 -4w = 0, w = 318/4 = 159/2= 79.5 ft

L =159 ft

max Area = 159(79.5)=12640.5 ft^2