To find the surface area of a rectangular prism you follow the formula SA = 2(wl+hl+hw) However, with this question we must scale the values up by 10. We do this by multiplying them by 10. The original values were 6, 2, and 1. The new ones are 60, 20, and 10. Now all we do is plug them into the formula.
See :
SA = 2(wl+hl+hw) SA = 2 (20 · 60 + 10 · 60 + 10 · 20)
This may look scary but once you simplify it, it looks like this :
