The back of Alisha’s property is a creek. Alisha would like to enclosure a rectangular area, using the creek as one side and fencing for the other threee sides, to create a corral. If there is 180 feet of fencing available, what is the maximum possible area of the corral?

Answer 1

Area=xy
perimenter= 2x+y
or y=180-2x
area=x(180-2x)

now area is zero at x=0, and x=90
so max area must be half way between those roots, or x=45
Think about that, as area is a parabola. Max area is 1/2 way between roots.
Areamax=xy=45(180-90)=....