A Collinearity Involving an Excircle, the Incircle, and the Circumcircle
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Let ABC be a triangle with incenter I and circumcircle . Let J be the excenter of the excircle opposite A. Let IJ intersect BC at D and let IJ intersect
at M. Let N be the midpoint of arc MBA of
. Let S and T be the second intersection points of NI, NJ with
. Then S, D, T are collinear.
Contributed by: Jay Warendorff (March 2011)
Open content licensed under CC BY-NC-SA
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See collinear excircle.