MathDB
circles intersection is midpoint of chord, 3 circles (2014 Kyiv City MO 11.4.1)

Source:

August 6, 2020
geometrycirclesmidoint

Problem Statement

Construct for the triangle ABCABC a circle SS passing through the point BB and touching the line CACA at the point AA, a circle TT passing through the point CC and touches the line BABA at the point AA. The second intersection point of the circles SS and TT is denoted by DD. The intersection point of the line ADAD and the circumscribed circle ΔABC\Delta ABC is denoted by EE. Prove that DD is the midpoint of the segment AEAE.