The equation I get is: s = sqrt(d^2-c^2)/2 + sqrt(4*d^2-c^2)/2 + 3*d/2. I don't think it is easy to solve for d, so I didn't try. The square roots are intended to be the distance from the center of the chord to the center of each circle. My guess is that an equation in d^8 will result and I don't know whether that can be reduced.
Dan in NY
&&& "W.H." wrote: > > Two circles of diameter (d) and (2*d) overlap (not over the centres) > so that they have a common chord of length (c). The measurement across > the two circles perpendicular to the chord is (s) distance. I need to > find the diameters in terms of (c) and (s).