Answer: 3 inches tall
Explanation:
The formula for the volume of a cube is a to the power of 3
Substitute a with 6 and you get 6^3. 6 X 6 X 6 = 216 so the volume is 216 inches cubed.
The formula for the volume of a rectangular prism is length X width X height. If we substitute the length and with with 8 and 9, we get 8 X 9 X height = 216 (since the volume is the same.)
72 X height = 216. Divide both sides by 72 and you get 3 as an answer.