# Collinearity of an Incenter and Two Circumcenters

Collinearity of an Incenter and Two Circumcenters

Let ABC be a triangle with excentral triangle A'B'C'. Let I be the incenter and O the circumcenter of ABC, and let be the circumcenter of A'B'C'. Then I, O, and are collinear and O bisects .

O

e

O

e

IO

e