We will have the following:
*First. We determine a new point that can be used to complete the rigth triangle; we are given the points:

So, a point we could use to form a rigth triangle could be:

And we would have the following triangle:
*Second: We determine the distances:
**Distance on the horizontal axis would be 9 units.
**Distance on the vertical axis would be 8 units.
*Third: We determine the distance betweem the two original points:
![h=\sqrt[]{9^2+8^2}\Rightarrow h=\sqrt[]{145}](https://tex.z-dn.net/?f=h%3D%5Csqrt%5B%5D%7B9%5E2%2B8%5E2%7D%5CRightarrow%20h%3D%5Csqrt%5B%5D%7B145%7D)

So, the distance between the two original points is approximately 12 units.