How do you do this I’m confused?

Answer:
0.547 in.
Step-by-step explanation:
Volume for a rectangular prism is LxWxH.
--> First turn them into decimals:
* 1/2 = 0.5.
* 7/8 = 0.875.
* 1 1/4 = 1.25.
--> Now use the formula:
* 0.5 x 0.875 x 1.25 = 0.547.