A collection of $2000$ congruent circles
Source: Vietnam TST 2000
April 3, 2007
combinatorics proposedcombinatorics
Problem Statement
A collection of congruent circles is given on the plane such that no
two circles are tangent and each circle meets at least two other circles.
Let be the number of points that belong to at least two of the circles.
Find the smallest possible value of .