Explanation:
so, you got the volume but don't know how to find the surface area ? that is strange for me. what's the problem ?
the surface of a cube or rectangular prism consists of 6 sides that split (for a rectangular prism) into 3 pairs of equal sides :
top and bottom
left and right
front and back
all we need to do is calculate the areas of these 6 rectangles and add them up. that's it.
in our case
top and bottom : 5×4 × 2 = 20×2 = 40 in²
left and right : 4×4 × 2 = 16×2 = 32 in²
front and back : 5×4 × 2 = 40 in²
so, in total, the whole surface area of the prism is
40 + 32 + 40 = 112 in²