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
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IO
e