I hope the image is clear enough

There are 3 segmented circles, the centres are vertically above each other. The vertical distance between each is 'h'.

Top circle has radius R, centre circle radius (R+d) and bottom circle radius (R+2d).

All coloured triangles are right-triangles. The white and purple triangles are the same.

Given that a, b, c and h are known, is it possible to obtain equations for 'R' and 'd' in terms of these known quantities?

I feel sure that it should be possible

i.e. I known the unmarked side of the red triangle is etc

but am struggling to get anywhere with it.

Any help would be greatly appreciated.

Please say if you require any further info.