A Concurrency from Six Pedal Points

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Let ABC be a triangle and P and Q be two other points. Drop perpendiculars from P to the three sides of ABC. Let X, Y, and Z be the feet of the perpendiculars (pedals) of Q on the three perpendiculars. Let X', Y', and Z' be the pedals of P on AQ, BQ, and CQ. Then XX', YY", and ZZ' are concurrent.

Contributed by: Jay Warendorff (September 2008)
After work by: Darij Grinberg
Open content licensed under CC BY-NC-SA



The theorem is contained in "The Theorem on the Six Pedals", available on Darij Grinberg's home page.

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