MathDB
Two circles passing through a point on the altitude

Source: Baltic Way 2022/12

November 12, 2022
geometry

Problem Statement

An acute-angled triangle ABCABC has altitudes AD,BEAD, BE and CFCF. Let QQ be an interior point of the segment ADAD, and let the circumcircles of the triangles QDFQDF and QDEQDE meet the line BCBC again at points XX and YY , respectively. Prove that BX=CYBX = CY .