Question

A wall shaped like a trapezoid needs to be painted. The height of the wall is 16 feet and the bases are 20 feet and 24 feet. If one can of paint covers 20 square feet, how many whole cans of paint will the painter need to buy to paint the wall with one coat

Answer 1

18 cans

Explanation:

The number of cans of paint will be the least integer greater than or equal to the number required to cover the area of the trapezoid.

Area of a trapezoid

The area of the wall is given by the formula ...

A = 1/2(b1 +b2)h

where b1 and b2 are the bases, and h is the height.

We are given the values b1=20 ft, b2=24 ft, h=16 ft, so the area is found to be ...

A = 1/2(20 ft +24 ft)(16 ft) = 352 ft² . . . . . area of the wall

Cans of paint

Each can of paint covers 20 ft², so n cans of paint will cover 20n square feet. We want to find the minimum integer value of n that satisfies ...

20n ≥ 352

n ≥ 17.6 . . . . . . . . . divide by 20

The next larger integer is 18.

The painter will need to buy 18 cans of paint.