externally tangent circles, perpendicular chords, collinearity wanted
Source: INAMO Shortlist 2015 G2
May 14, 2019
geometrytangent circlescirclesperpendicularcollinear
Problem Statement
Two circles that are not equal are tangent externally at point . Suppose point is the intersection of the external common tangents of the two circles. Let and are two points on different circles so that is perpendicular to . Show that the line passes through .