Answer:
54 yd²
Explanation:
The area of a trapezoid can be found using the formula ...
... area = (1/2)(b1 +b2)(h)
where b1 and b2 are the lengths of the parallel bases, and h is the height. Putting your numbers into the formula gives ...
... area = (1/2)(9 yd + 18 yd)(4 yd) = 54 yd²