Every 1/2 hour naomi s stretches her neck every 1/3 at work she stretches her legs and everyone 6 hour she stretches her arms which part of her body will naomi stretch when two thirds of an hour has passed

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.