Answer:
D perimeter = 40 ft
Step-by-step explanation:
area square = s · s = s²
preimeter square = s+s+s+s = 4s
Given area = 100 ft²
area square = s²
√area square = s
perimeter = 4s
perimeter = 4 · (√area square)
perimeter = 4 · (√100)
perimeter = 4 · (10)
perimeter = 40 ft