Let points P1,P2,P3,…,Pn−1 divide the side BC of △ABC into n parts. Let r1,r2,r3,…,rn be the radii of the incircles and let p1,p2,…,pn be the radii of the excircles corresponding to vertex A for triangles ABP1, AP1P2, …, APn−1C. Let r and p be the corresponding radii for triangle ABC. Show that p1r1⋅p2r2⋯pnrn=pr.