You can put this solution on YOUR website! Imagine you have two scalene triangles put together with leg 10 and hypotenuse 15
Then, 10^2 + b^2 = 15^2 by the Pythagorean theorem. 100 + b^2 = 225
b^2 = 125
b = sqrt(125) = 5*sqrt(5)
I hope that this helped!
If this was not detailed enough please e-mail me at onlyyourmathtutor@yahoo.com.