Hello! To find the volume of a triangular prism you need to start by using the formula A=1/2hb therefore in this problem 3 is the height and 7 is the base, you multiply those two and then half your answer. That equation is equal to the capital B in the next equation. V=Bl or in this case V=B(11) once you do that you should have your answer. I hope this helps!! Let me know if you have any questions.
