A triangular prism. The rectangular sides are 8 inches by 4 inches, 8 inches by 5 inches, and 8 inches by 3 inches. The triangular sides have a base of 4 inches and height of 3 inches.
The area of each triangular base is:

A = 1/2(b)(h) A = 1/2(4)(3)

A = in.2
There are two bases, so total base area is in.2.
The lateral area is:

A = 8(4) + 8(3) + 8(5)

A = in.2
The total surface area is in.2