MathDB
angle bisectors in triangle, segments equal

Source: Bulgaria 1992 P5

May 18, 2021
geometryTriangles

Problem Statement

Points D,E,FD,E,F are midpoints of the sides AB,BC,CAAB,BC,CA of triangle ABCABC. Angle bisectors of the angles BDCBDC and ADCADC intersect the lines BCBC and ACAC respectively at the points MM and NN, and the line MNMN intersects the line CDCD at the point OO. Let the lines EOEO and FOFO intersect respectively the lines ACAC and BCBC at the points PP and QQ. Prove that CD=PQCD=PQ. (Plamen Koshlukov)