when we unfold a box, it makes it easier to see how we actually figure out surface area. in the unfolded or exploded view, we are finding the area of each section..
3 x 12
5 x 3 5 x 12 5 x 3 (the outsides are the wings)
3 x 12
5 x 12
if we multiply each of the sections and add them up...we get 222.