# Four Concyclic Points

Requires a Wolfram Notebook System

Interact on desktop, mobile and cloud with the free Wolfram Player or other Wolfram Language products.

Let ABC be a triangle and H the foot of the altitude from B. Let M be the midpoint of AC. Let P and Q be the feet of the perpendiculars from A and C to the angle bisector of the angle ABC. Then H, M, P and Q lie on a circle.

Contributed by: Jay Warendorff (April 2008)

After work by: D. Grinberg

Open content licensed under CC BY-NC-SA

## Snapshots

## Details

D. Grinberg, "From Baltic Way to Feuerbach: A Geometrical Excursion," *Mathematical Refections *(2), 2000 p. 2.

## Permanent Citation

"Four Concyclic Points"

http://demonstrations.wolfram.com/FourConcyclicPoints/

Wolfram Demonstrations Project

Published: April 2 2008