Kazakhstan MO 2018
Source: Kazakhstan MO 2018 final round.Grade 11;Problem 1
May 4, 2018
geometryKazakhstan
Problem Statement
In an equilateral trapezoid, the point is the midpoint of the base . A circle with a center at a point and a radius is tangent to a straight line . Let the segment intersect this circle at point , and let is a point such that is a parallelogram. The circumscribed circle of a triangle intersects the segment at a point . Prove that .