# Collinearity of a Triangle's Circumcenter, Incenter, and the Contact Triangle's Orthocenter

Collinearity of a Triangle's Circumcenter, Incenter, and the Contact Triangle's Orthocenter

Let I and O be the incenter and circumcenter of a triangle. Let H be the orthocenter of the triangle's contact triangle (the triangle formed by the points of contact of the incircle with the sides). Then I, O, and H are collinear.