The Sum of the Circumradii of Three Subtriangles
Let ABC be a triangle. Let A'A'', B'B'', and C'C'' be tangents to the incircle of ABC and parallel to BC, AC, and AB, respectively, so that A'', B' are on AB, B'', C' are on BC, and C'', A' are on CA . Let be the circumradius of ABC and , , and be the circumradii of AA'A'', BB'B'', and CC'C'', respectively. Then .