The figure consists of,
A rectangle with dimension 15 ft by 7 ft.
Two triangles with base b = 7 ft and height h = 5 ft.
A rectangle with dimension 15 ft by 5 ft.
A rectangle with dimension 15 ft by 8.6 ft.
Determine the surface area of triangular prism.
So, surface area of triangular prism is 344 square feet.