I'm pretty sure the area of the figure is 88 ft.
To find DE, you do 8^2 + DE^2 = 10^2
so, 64 + DE^2 = 100
-64 -64
DE^2 = 36
So, DE is 6. Then find the area of a trapezoid like normal, so ((a + b)/2)h
a is 8, b is 14, and h is 8, so 8 + 14 = 22 and divide that by 2 and multiply it by 8 and you have 88.