Answer:
D. 84 ft^2
Explanation:
Formula for area of a trapezoid:
where a and b = bases and h = height
The trapezoid shown has the following dimensions
base 1 = 9ft
base 2 = 12ft
height = 8ft
Using the following information we plug in the values into the formula

Hence, the area of the trapezoid is 84ft² and your answer is D