Mikes music sold 287 cds on the first-day a sale. the store sold 96 more cds on the second dastaan on first day. how many cds in all were sold during the second day sale?

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.

4444444444444 i think