title: Get radius of circle, when know height and width of part of including square
body: <p>Know width and height of square's part, which include circle.
  How I can get radius of that circle?<a href="https://i.stack.imgur.com/XoCU5.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/XoCU5.jpg" alt="enter image description here"></a> </p>
  
  <p>UPDATE: How to get radius of LARGEST circle, part of which could be placed inside known rectangle  </p>