Here are more details leading to a possible solution.

Notice that the radius of the blue circle is s-a, the radius of the purple circle is s, and the radius of the circle inscribed in the little right triangle (whose sides are a,b,c) is s-c. There is also a 4th circle, not shown, whose radius is s-b.

## 2 replies on “Polarisation”

Here are more details leading to a possible solution.

Notice that the radius of the blue circle is s-a, the radius of the purple circle is s, and the radius of the circle inscribed in the little right triangle (whose sides are a,b,c) is s-c. There is also a 4th circle, not shown, whose radius is s-b.