The picture contains 2 squares. We should determine the side of the square before finding the area.
First, the bigger square
one of the side is 8 ft
one of the side is 10 - 2 = 8 ft
Second, the smaller square
both of the sides are each 2 ft
Third, find the area
a = first area + second area
a = s × s + s × s
a = 8 × 8 + 2 × 2
a = 64 + 4
a = 68
The area of the square is 68 ft²