the surface area of a rectangular prism is computed as follows:
[tex]SA=2\cdot(l\cdot w+l\cdot h+h\cdot w)[/tex]where l is length, h is height and w is width.
Substituting with l = 5, w = 6 and h = 14, we get:
[tex]\begin{gathered} SA=2\cdot(5\cdot6+5\cdot14+14\cdot6) \\ SA=2\cdot(30+70+84) \\ SA=2\cdot184 \\ SA=368ft^2 \end{gathered}[/tex]