Dan wanted to paint his house. Each gallon of paint will cover 115 square feet. Dan plans to paint approximately 3080 square feet of wall space. Which is closest to the number of cans of paint Dan will need to buy?
10
20
30
40

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.