(V.Protasov, 10-11) Given parallelogram ABCD such that AB \equal{} a, AD \equal{} b. The first circle has its center at vertex A and passes through D, and the second circle has its center at C and passes through D. A circle with center B meets the first circle at points M1, N1, and the second circle at points M2, N2. Determine the ratio M1N1/M2N2. ratiogeometryparallelogramgeometry proposed