Question

Look at this rectangular prism:

89 ft
16 ft
50 ft


If all three dimensions are doubled, then which of the following statements about its surface area will be true?

Answer 1

Quadrupled — the surface area becomes 4 times as large.

Reason: For dimensions l, w, h the surface area is 2(lw + lh + wh). If each dimension is doubled, new SA = 2((2l)(2w)+(2l)(2h)+(2w)(2h)) = 2·4(lw+lh+wh) = 4·(original SA).

(Also: volume would increase by 2^3 = 8.)