Which one of these answers is correct?

Question

anonymous · Answer

http://openstudy.com/study#/updates/4fecfee5e4b0bbec5cfc8287 or http://openstudy.com/study#/updates/4fe11c16e4b06e92b87049dd

anonymous · Answer

Two people on OpenStudy gave two different answers to a question I need the answer to.

hba · Answer

3/

12/16 = 216/X
crossmultiply
12x = 3456

x = 288 square inches for the larger one.

hba · Answer

The second link

anonymous · Answer

Okay thank you!!!

hba · Answer

Your'e Welcome.

phi · Answer

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?

The KEY IDEA is that when you scale the length of a 3 dimensional figure, to get a similar (but larger) figure,  you scale each dimension.   For a simple figure, say a cube, you see that if a side goes from s  to 2s , then the area goes from s*s   to (2s)*(2s)  or 4s^2
in other words,  the area goes as the square of the scale factor.

In this problem,  the scale factor is 18/12 = 3/2
that means the area of the larger prism  will scale as 9/4
9/4 * 192 is the answer