intersection points of common tangents of 2 circles are concyclic
Source: Indonesia INAMO Shortlist 2017 G2 https://artofproblemsolving.com/community/c1101409_indonesia_shortlist__geometry
November 15, 2021
Concycliccommon tangentscommon tangentgeometry
Problem Statement
It is known that two circles have centers at and . Prove that the intersection points of the two internal common tangents of the two circles with their two external common tangents lie on the same circle.