Acamera manufacturer spends $1600 each day for overhead expenses plus $9 per camera for labor and materials. the cameras sell for $17 each. how many cameras must the company sell in one day to equal its daily cost? if the manufacturer can increase production by 50 cameras per day, what would their daily profit be?

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.