This problem asks for the surface area of the box, since the contact paper covers the outside (like wrapping paper). The box is 11 x 8 x 9, its length, width, and heighth respectively. And the formula for the surface area of the box is
SA = 2(lw + wh + hl)
SA = 2(11*8 + 8*9 + 9*11)
SA = 2(88 + 72 + 99)
SA = 2(259)
SA = 508 square inches
We are told the contact paper costs eight cents a square inch.
508 square inches x 8 cents / square inch
= $41.44 (the square inches divide out)
Thus, Erin spent $41.444 on contact paper.
