Answer:
400 sq. ft.
Explanation:
We gotta find the length of a side:
First, we divide 80 by 4, because the perimeter of a square is (4 x side):
80 ft. / 4 = 20 ft.
Second, we doing the normal area of a square equation:
= 400 square ft.
Which leads to out answer of 400 sq. ft.