# A Concurrency of Lines Joining Orthocenters

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Let ABC be a triangle with incenter I. Let A', B' and C' be the excenters opposite A, B, and C, respectively. Then the lines joining the orthocenters of IBC and A'BC, IAC and B'AC, and IAB and C'AB are concurrent.

Contributed by: Jay Warendorff (March 2011)

Open content licensed under CC BY-NC-SA

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## Permanent Citation

"A Concurrency of Lines Joining Orthocenters"

http://demonstrations.wolfram.com/AConcurrencyOfLinesJoiningOrthocenters/

Wolfram Demonstrations Project

Published: March 7 2011