AO = OC wanted, <DBA = <CBP, # ABCD
Source: Polish Math Olympiad 2021 2nd round p2 day 1
May 31, 2021
equal segmentsparallelogramequal anglesgeometry
Problem Statement
The point P lies on the side of the parallelogram with . Point is the center of the circle passing through the points and and tangent to the straight line at point . Prove that .