Answer:
132 units²
Explanation:
The figure is a trapezoid, so its area can be found using the formula for the area of a trapezoid.
A = 1/2(b1 +b2)h
The top "base" is the difference between 21 units and 9 units, so is 12 units. Filling in the numbers, we have ...
A = 1/2(21 units +12 units)(8 units) = 132 units²
The area of the figure is 132 square units.