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 2.5 feet and a height of 3.5 feet. Compare 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.

Answer 1

The amount of paint required to paint the whole cupboard is:

$2\times2.5^2+4\times(2.5\times3.5) \\=47.5 ft^2$

The amount of paint required to paint all but the bottom surface is:

$2.5^2 + 4(2.5\times3.5) \\= 41.25 ft^2$

So the difference in paint required is 6.25 square feet worth of paint.