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