What is the difference in surface areas, in square feet, of the two boxes?
Rectangular Prism: 3 ft by 4.5 ft by 2 ft
Cube: 3 ft

The difference is 3ft since the surface area for the prism is 57, and the surface area for the cube is 54.

You can use the surface area formula
2(wl+hl+hw) = Area
2·(3·4.5+2·4.5+2·3)=57

And a cubes surface area formula
6a^2 = Area
6·32=54