Write an equation to represent to write each

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.

the answer is 62.8 cubic units

this may not be at all, but i use the same website you're using for school, and if i'm stuck doing one of these i try to look for it on the section.