Press Space to see the right triangle change after using the sliders. A and B sides are labeled in case you want to know what changes. Default when opened is a 160, 120, 200 right triangle, which is just a multiple of the classic 3, 4, 5 right triangle.
Made project in Desmos and this is what It looks like: https://www.desmos.com/calculator/1pvnmowarn Red radius is simple to find as long as you have all three sides of the right triangle. Blue radius is the reason this project was made and took some fun math! This could actually be implemented in some projects like triangle renderers if you understand the concept. I would recommend looking at the Desmos project to understand it, or comment on this project or on my page. I will gladly try to teach or help you. I found out how to do this on my own, and yes I know people have already found this out before but I decided to make this myself. <3 Equations made in Desmos for the secondary circle. Yes you can have a circle on the other empty place of the right triangle, but this is just the proof of how to do it in that one spot for fun. Equations: https://www.desmos.com/calculator/1clztlpxsl
