MathDB
Points on the circle

Source: China TST 2007, Problem 3

December 29, 2008
algorithmcombinatorics unsolvedcombinatorics

Problem Statement

There are 63 63 points arbitrarily on the circle C \mathcal{C} with its diameter being 20 20. Let S S denote the number of triangles whose vertices are three of the 63 63 points and the length of its sides is no less than 9 9. Fine the maximum of S S.