I forget how to do these type of word problems.

Assume you working on the house pictured below. The length of the house is 50 feet, the width is 30 feet, and from the ground to the gable (the height of the rectangle) is 10 feet. The height of the triangular prism on top is 6.5 feet.
The owner of the house wants to estimate the amount of paint needed for the house. If one gallon of paint is expected to cover 400 square feet of surface, how many full gallons of paint will be needed?

2 answers

area of walls: 2(50*10 + 30*10) = 1600
area under roof: 2(1/2 * 30 * 6.5) = 195

total area: 1795 ft^2

gallons = 1795ft^2 / 400ft^2/gal = 4+ gals, or 5 gallons
Thank you Steve this helped me!