MathDB
Interesting problem of a triangle (equal chords)

Source: 10th Iberoamerican 1995 pr. B2

March 30, 2004
geometrytrapezoidtrigonometrysimilar triangles

Problem Statement

The incircle of a triangle ABCABC touches the sides BCBC, CACA, ABAB at the points DD, EE, FF respectively. Let the line ADAD intersect this incircle of triangle ABCABC at a point XX (apart from DD). Assume that this point XX is the midpoint of the segment ADAD, this means, AX=XDAX = XD. Let the line BXBX meet the incircle of triangle ABCABC at a point YY (apart from XX), and let the line CXCX meet the incircle of triangle ABCABC at a point ZZ (apart from XX). Show that EY=FZEY = FZ.