The Distance Formula

Normally I pride myself on not deriving anything, since 99% of the time that infuriates students. However, in the case of the distance formula, I've found over my years of tutoring that showing how it came from the Pythagorean Formula is actually really helpful for students trying to memorize and use the formula. So I do that here. But if you hate it, you can always skip the first half of the video! Don't miss the word problem though.