A Congruent Angle inside the Incircle

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Let ABC be a triangle and let O be the center of the incircle. Let E be the point of tangency of the incircle with AC. Let AO and CO intersect the line drawn through the other two points of tangency at F and D, respectively. Then .
Contributed by: Jay Warendorff (March 2011)
After work by: Antonio Gutierrez
Open content licensed under CC BY-NC-SA
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Details
The statement of the theorem is in Problem 52. Triangle, Angles, Incircle.
Permanent Citation
"A Congruent Angle inside the Incircle"
http://demonstrations.wolfram.com/ACongruentAngleInsideTheIncircle/
Wolfram Demonstrations Project
Published: March 7 2011