Let's say I have a point1: x =10, y = 50 

and point2: x = 30, y = 75

And I would like to draw a line between those two points. How to calculate the distance between those two points so I know what that line's length should be?

Thanks. 

With all due respect, I googled your thread title verbatim and was suggested a 25-second video clip with a thumbnail of the literal equation required to do what you're asking.  Didn't even have to change it at all.  That points to a serious lack of effort.

We're all willing to help people and answer questions, but that effort needs to be reciprocated at least somewhat by the people asking.  Please at least use a few minutes to google for an answer before making a thread asking something.

2 hours ago, Abdou23 said:

 

 

Check out this link:

http://www.mathwarehouse.com/algebra/distance_formula/index.php

Hopefully that gives you all the info you need.  If you're still having problems or dont understand the theory, let me know.

To calculate the distance between 2 points (x,y) and (a,b). You use Pythagoras' theorem:

Distance = sqrt[ (b-y)^2 + (a-x)^2 ]