MathDB
circles tangent to a fixed circle (2019 Novosibirsk Oral Geo Oly 8.6)

Source:

April 28, 2021
geometryfixedtangent circles

Problem Statement

Point AA is located in this circle of radius 11. An arbitrary chord is drawn through it, and then a circle of radius 22 is drawn through the ends of this chord. Prove that all such circles touch some fixed circle, not depending from the initial choice of the chord.