Pond fencing problem

Question

A landscaper has 120 meters of fencing and wants to enclose a rectangular garden next to a straight pond, using the pond as one of the longer sides of the rectangle. Fencing is only required for the remaining three sides (the two short sides and the side opposite the pond).

What dimensions will maximize the enclosed area? Additionally, what is the maximum area that can be enclosed?

subway surfers

Answer 1

60-30-30 m for sides

area = 60(30) = 1800 m^2

area = sL

120 = L +2s

L = 120-2s

area = s(120-2s) = 120s -2s^2

A' = 120 -4s = 0

4s = 120

s = 120/4 = 30

L = 120-2(30) = 60