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:
The height is 10.
The volume is 280.
Substituting into the formula, let's sovle for "h". Shown below:
Answer7 ft