A triangular prism has a length of 12 inches. A larger similar triangular prism has a length of 18 inches. If 192 square inches of paper is used to wrap the smaller prism with minimum wastage, approximately how many square inches of paper will be required to wrap the larger prism?

Question

A triangular prism has a length of 12 inches.  A larger similar triangular prism has a length of 18 inches.   If 192 square inches of paper is used to wrap the smaller prism with minimum wastage, approximately how many square inches of paper will be required to wrap the larger prism?

anonymous · Answer

Looks like a proportion situation:

I'd start with the idea that 12 is to 18 as 192 is to x.  You can set those up as fractions.

12/18 = 192/x   From here you can cross multiply

12(x) = 3456   Then divide by 12 on both sides

x = 288 sq. in.