MathDB
3 of 51 vertices of 101-regular polygon are vertices of an isosceles

Source: Czech-Polish-Slovak Junior Match 2012, Individual p4 CPSJ

March 11, 2020
polygonregular polygoncombinatoricscombinatorial geometryisosceles

Problem Statement

Prove that among any 5151 vertices of the 101101-regular polygon there are three that are the vertices of an isosceles triangle.