An Altitude and Four Concyclic Points

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Let ABC be a triangle and let A' be the foot of the altitude from A. Let P and Q be the perpendicular projections of A' onto AB and AC, respectively. Then B, C, P, and Q are concyclic.

External Links

Altitude (Wolfram MathWorld)
Concyclic (Wolfram MathWorld)
Perpendicular (Wolfram MathWorld)

Permanent Citation

Jay Warendorff
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​"An Altitude and Four Concyclic Points"​
​http://demonstrations.wolfram.com/AnAltitudeAndFourConcyclicPoints/​
​Wolfram Demonstrations Project​
​Published: March 7, 2011