Joe skipped his class. after class his mom got a call of the school saying that he skipped class. joe was running away from mom knowing that mom will hit him with the new belt his dad bought what should joe do in this moment ?

tell a teacher at school or call child sevices.

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.