Remember you can only add x's together if they have the same power. This makes sense why you can 2 to -1 because they are both the same power of x, x^0. (which equals 1 by default)
V ( cylinder ) = r² π h V ( cone ) = 1/3 r² π h A cone that fits exactly inside the cylinder has the volume: V ( cone ) = 1/3 V ( cylinder = 1/3 · 81 = 27 ft³
The cube-shaped box has a volume of 216 cubic inches. The rectangular box has a volume of 160 cubic inches. Therefore, the answer is C) 56 cubic inches.