Question

I need help with this

Answer 1

for a triangular prism, its volume will simply be area of its base times its length.

the are of the base for this one is simply any of those triangular bases.  Now, let's notice, the right-triangle has a base of 9 and a height o 9, notice the tickmarks, whilst the prism also has a length of 13.

$\bf \stackrel{\textit{area of the triangle}}{\cfrac{1}{2}(9)(9)}~~\cdot~~ \stackrel{\textit{length}}{(13)}\implies 9\cdot 13\implies 117$