Joel earns a commission of 5% on the audio equipment he sells , and the store keeps the rest . he sells a $750 amplifier. a. how much commission does joel earn from the sale ? b. how much does the store keep ?

Joel earns $35.00 commission and the store keeps $715.

Step-by-step explanation:

You need to figure 5% of what he sold - or 5% of $750.

Of course, you can use a calculator, or multiply $750 by .05. I prefer to think of 10 percent ($75.00) and half that to get 5%. $35.00.

Joel earns $35.00 on the sale. Not bad!

If he gets to keep $35, deduct this from the price to find out how much the store will keep.

$750 - $35 - $715.

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.