MathDB
property of line connecting tangent points of two circles to a third one

Source: Sharygin 2006 finals 9.1

September 12, 2019
tangent circlescirclesgeometry

Problem Statement

Given a circle of radius KK. Two other circles, the sum of the radii of which are also equal to KK, tangent to the circle from the inside. Prove that the line connecting the points of tangency passes through one of the common points of these circles.