MathDB
Line, passing 2 ants, tangent to a fixed circle

Source: Saint Petersburg olympiad 2024, 9.3

September 21, 2024
geometry

Problem Statement

The triangle ABCABC is inscribed in a circle. Two ants crawl out of points BB and CC at the same time. They crawl along the arc BCBC towards each other so that the product of the distances from them to point AA remains unchanged. Prove that during their movement (until the moment of meeting), the straight line passing through the ants touches some fixed circle.