Cherese needs to buy some cardboard to build a box 10 inches long, 9 inches wide, and 7 inches high. If she purchases 500 square inches of cardboard, how much will be left over?
446 in.²
426 in.²
54 in.²
406 in.²
The total surface area of the box can be calculated by finding the surface area of each side and adding them up.
Surface area of the box = 2lw + 2lh + 2wh
Surface area = 2(10*9) + 2(10*7) + 2(9*7)
Surface area = 180 + 140 + 126
Surface area = 446 square inches
Cherese purchases 500 square inches of cardboard, so the amount left over is:
500 - 446 = 54 square inches
Therefore, the answer is 54 in.².