Here's the question you clicked on:
InsanityxP
What is the volume of the prism? ~attachment in comments~
The volume of a prism is area times length. Think you can go from there?
I know the formula I just need the process explained.
Find the area of the triangle, then multiply that by the length of the actual prism, which is 10 here.
Area of the triangle = base x height / 2