This problem was posted at Konnō Hachiman shrine in Tokyo in 1824. Here is its entry at the [url=https://sangaku-archive.org/works/1864_Tokyo_Konno_273]Sangaku Archive[/url][color=rgba(0, 0, 0, 0.87)].[/color]
Three circles and a line are mutually tangent, as shown below. Find an equation that relates the radii of the three circles.