Cheryl has a box that is in the shape of a rectangular prism. its height is twice the length, its length is 3 times the width, and the width measures 7 inches.

L=3W, H=2L, so H=6W

Since W=7, the dimensions would be:

W=7in, L=21in, H=42in

The surface area of any rectangular prism is:

A=2(LW+LH+WH), and since W=7, L=21, H=42

A=2(21*7+21*42+7*42)

A=2(147+882+294)

A=2(1323)

A=2646 in^2

The volume would be:

V=LWH, since L=21, W=7, H=42

V=21*7*42

V=6174 in^3

You question didn't really specify what you were looking for, so I did the best I could, if you need more info, just ask in the comments. :)