Hello, 3Coli here!
Here is the answer to your question:
The variable B stands for the area of the base.
In this prism, B equals 38.5 in.^2
The variable H stands for height.
In this prism, h is 9 in.
The volume of the prism is 346.5 in.^3
Hopefully, this helps! :D
Good luck with your assignment.