The Distance Formula is a variant of the Pythagorean Theorem that you used back in geometry. Here’s how we get from the one to the other:

Suppose you’re given the two points (–2, 1) and (1, 5), and they want you to find out how far apart they are. The points look like this:

You can draw in the lines that form a right-angled triangle, using these points as two of the corners:

It’s easy to find the lengths of the horizontal and vertical sides of the right triangle: just subtract the x-values and the y-values:

Then use the Pythagorean Theorem to find the length of the third side, which is the hypotenuse of the right triangle:

## Distance Formula Video Tutorials