Answer:
172 cm^2
Explanation:
Since it is a rectangular prism, you would have 6 sides, with two of them being the same. Each side is the values but multiplied by each other. So 7x2, 8x2, and 7x8. If you add them up it would be 14+16+56= 86, but that is only 3 sides, so you need to multiply 86 by 2, thus 172.