Answer:
24.1 square units
Explanation:
You want the base area of a prism with height 9 units and volume 216.9 units³.
Volume
The formula for the volume of a prism is ...
V = Bh
where B is the area of the base, and h is the height. Solving for the base area, we have ...
B = V/h = (216.9 u³)/(9 u) = 24.1 u²
The area of one of the bases is 24.1 square units.