JoAnn has 2/3 of an hour in which to do her math homework. It takes her 1/12 hour to do each math problem. How many problems can JoAnn complete in 2/3 of an hour? 23÷112=□

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.

just get this app called photo math it should be able to do those

the answer is d

step-by-step explanation:

you can also use mathway to get you answer + steps