what is the distance formula. ​

Distance formula: 

https://www.screencast.com/t/2b4GDp2N

Hope this helps! : )

I could just tell you....but I want to explain it, so that you don't have to just memorize it! 

Say we want to know the distance between these two points: (1, 2) and (4, 6)

The length of the purple line is the distance between them.

Hey! We can make a right triangle out of this, with the purple line as the hypotenuse. Now we can use the Pythagorean theorem to find the length of the purple line, which I called c.

3² + 4² = c²

25 = c²

5 = c

And the distance formula comes from the Pythagorean theorem.

(difference in x's)² + (difference in y's)² = (distance between the two points)²

\(\sqrt{(x_1-x_2)^2+(y_1-y_2)^2}=\text{distance between the two points}\)

And that is the distance formula! 

Here's a better explanation: https://www.youtube.com/watch?v=nyZuite17Pc