We have to put the triangular side as the base.
So, the height of the tent is signified by the red line, h.
Shown below:
The volume of the triangular prism is area of triangle x height
V = A_T x h
Let's find the area of the triangle, A_T:
[tex]\begin{gathered} A_T=\frac{1}{2}bh \\ A_T=\frac{1}{2}(8)(h)_{} \\ A_T=4h \end{gathered}[/tex]
The height is 10.
The volume is 280.
Substituting into the formula, let's sovle for "h". Shown below:
[tex]\begin{gathered} V=A_T\times h \\ 280=4h\times10 \\ 40h=280 \\ h=\frac{280}{40} \\ h=7 \end{gathered}[/tex]Answer7 ft
