Question

The volume of this right trapezoidal prism is 464.75 ft³. What is the height, x, of the prism? Enter your answer as a decimal in the box.

Answer 1

Check the picture below.

so the volume is really just the product of the trapezoidal face and the length, and we know is 464.75 ft³.

$\textit{area of a trapezoid}\\\\ A=\cfrac{h(a+b)}{2}~~ \begin{cases} h=height\\ a,b=\stackrel{parallel~sides}{bases}\\[-0.5em] \hrulefill\\ h=5\\ b=8\\ a=5 \end{cases}\implies A=\cfrac{5(5+8)}{2}\implies A=\cfrac{65}{2}~ft^2 \\\\[-0.35em] ~\dotfill\\\\ \stackrel{\textit{\large volume of the prism}}{\stackrel{\textit{area of trapezoid}}{\left( \cfrac{65}{2} \right)} \stackrel{length}{(x)}}~~ = ~~464.75\implies \cfrac{65x}{2}=464.75 \\\\\\ 65x=(2)464.75\implies x=\cfrac{(2)464.75}{65}\implies x=14.3$