HELP Using the distance formula, calculate how far Hector threw the ball. (4 points: 2 points for setup, 1 for calculation, 1 for the answer).
HEL

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.

addition

step-by-step explanation:

use distributive property on all like terms and change your signs if you have a double negative or if you have positive/negative