drag the end points to move the line slope is how high the line went compered to how far to the right you went. so if you travel 1 to the right and the line goes 2 up the slope is 2. so for 1 right and 3 up the slope is 3. (if the line goes down when you go right the value is negative)
code by me background by scratch my other program that I based on this https://scratch.mit.edu/projects/515340311/