An Angle Bisection
Let ABC be a triangle and let A', B', and C' be the contact points of the incircle opposite A, B, and C, respectively. Let H be the foot of the perpendicular to A'C' from B'. Then B'H bisects AHC.
The statement of the theorem is in Triangle: Incircle, Perpendicular, Angle Bisector.
"An Angle Bisection"
Wolfram Demonstrations Project
Published: March 7 2011