Question

Enya is building a storage cupboard in the shape of a rectangular prism. The rectangular prism has a square base with side lengths of 2.4 feet and a height of 3.4 feet. Find the percentage of the amount of paint she would use to paint all but the bottom surface of the prism to the amount she would use to paint the entire prism. Round to the nearest tenth.

Answer 1

The top and bottom have area (2.4 ft)² = 5.76 ft².

The sides have area (4*2.4 ft)*(3.4 ft) = 32.64 ft².

The the total area is (2*5.76 +32.64) ft² = 44.16 ft². All but the bottom area is then 44.16 ft² -5.76 ft² = 38.40 ft².

The ratio (all but bottom area)/(total area) is then
  38.40/44.16 ≈ 87.0%