MathDB
2020 EGMO P3: Symmetric concurrence of angle bisectors in hexagon

Source: 2020 EGMO P3

April 18, 2020
geometryangle bisectorEGMO 2020EGMO

Problem Statement

Let ABCDEFABCDEF be a convex hexagon such that A=C=E\angle A = \angle C = \angle E and B=D=F\angle B = \angle D = \angle F and the (interior) angle bisectors of A, C,\angle A, ~\angle C, and E\angle E are concurrent.
Prove that the (interior) angle bisectors of B, D,\angle B, ~\angle D, and F\angle F must also be concurrent.
Note that A=FAB\angle A = \angle FAB. The other interior angles of the hexagon are similarly described.