garden
max area is if the sides are as equal as possible
so he should try to make a square (ideal is a circle, but barn walls are normally straight)
squaer perimiter=4 times legnth of 1 side
perimiter=amount of fencing=80
80=4s
divide 4
20=s
one sides=20
area=legnth times width
in squaer, legnth=width
20=legnth
20=width
area=20 times 20=400
dimetions are 20ft by 20ft to give 400ft^2
(fun fact, if it were a circle, the area would be about 509.5ft^2)
answer is 20ft by 20ft and area=400ft^2
