Let △ABC have incenter I and centroid G. Suppose that PA is the foot of the perpendicular from C to the exterior angle bisector of B, and QA is the foot of the perpendicular from B to the exterior angle bisector of C. Define PB, PC, QB, and QC similarly. Show that PA,PB,PC,QA,QB, and QC lie on a circle whose center is on line IG. geometryincenterexterior angleangle bisector