Area = (L1 + L2)*h/2
Area = 18
L1 + L1 = 6
h = ???
18 = (L1 + L2)*h/2
18 = (6) * h/2 Multiply both sides by 2
36 = 6h Divide by 6
36/6 = h
h = 6
So the square is 6 by 6
Area square = s^2 where s is the side of the square.
Area = 6^2 = 36
so your answer will be 6^2 = 36