A car dealer is calculating the list price for a used car. The dealer takes the initial price of the car and adds $259 dollars for cleaning and shipping the car to the dealer. The dealer then increases that price by 25% for the dealer’s profit. That price is then increased again by 10% for the salesperson’s commission. If a used car is initially priced $10,000, what will be the list price for this car?

Add the 259 to the initial price:

10,000 + 259 = 10,259

Increase that price by 25%, so multiply by 1.25:

10259 x 1.25 = 12,823.75

The price is then increased by another 10%, multiply by 1.10:

12,823.75 x 1.10 = 14,106.13

List price = $14,106.13

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.

the one below it is a function