Question

Area of prism
thank you

Answer 1

Check the picture below.

so the base of the pyramid is a triangle whose base is 12 and altitude is "x", and the pyramid has a height/altitude of 15, so

`\textit{volume of a pyramid}\\\\ V=\cfrac{1}{3}Bh ~~ \begin{cases} B=\stackrel{base's}{area}\\ h=height\\[-0.5em] \hrulefill\\ B=(1)/(2)(12)(x)\\[1em] h=15\\ V=240 \end{cases}\implies 240=\cfrac{1}{3}\left[\cfrac{1}{2}(12)(x) \right](15) \\\\\\ 240=30x\implies \cfrac{240}{30}=x\implies 8=x`