circle
Source: Canada 2005
June 26, 2009
geometrycircumcirclecombinatorics proposedcombinatorics
Problem Statement
Let be a set of points in the interior of a circle.
Show that there are three distinct points and three distinct points on the circle such that is (strictly) closer to than any other point in , is closer to than any other point in and is closer to than any other point in .
Show that for no value of can four such points in (and corresponding points on the circle) be guaranteed.