MathDB
Excircles & angle bisectors

Source: German TST 2004, Exam V, Problem 1

May 1, 2004
geometryparallelogramtrigonometryangle bisectorgeometry proposed

Problem Statement

The AA-excircle of a triangle ABCABC touches the side BCBC at the point KK and the extended side ABAB at the point LL. The BB-excircle touches the lines BABA and BCBC at the points MM and NN, respectively. The lines KLKL and MNMN meet at the point XX. Show that the line CXCX bisects the angle ACNACN.