A triangular prism. The rectangular sides are 12 feet by 3 feet, 12 feet by 5 feet, and 12 feet by 4 feet. The 2 triangular sides have a base of 3 feet and height of 4 feet.
The area of each triangular base is:
A = 1/2(b)(h)
A = 1/2(3)(4)
A =
ft2
There are two bases, so total base area is
ft2.
The lateral area is:
A = (12)(3) + 12(5) + 12(4)
A =
ft2
The total surface area is
ft2.