MathDB
Tangent to Circumcirlce

Source: 2013 Baltic Way, Problem 12

December 31, 2013
geometrycircumcircletrapezoidgeometry unsolved

Problem Statement

A trapezoid ABCDABCD with bases ABAB and CDCD is such that the circumcircle of the triangle BCDBCD intersects the line ADAD in a point EE, distinct from AA and DD. Prove that the circumcircle oF the triangle ABEABE is tangent to the line BCBC.