TOT 131 1986 Autumn S7 21 points on a circle, angle of arc <=120
Source:
August 29, 2019
combinatoricscombinatorial geometryarcanglespointscircle
Problem Statement
On the circumference of a circle are points. Prove that among the arcs which join any two of these points, at least of them must subtend an angle at the centre of the circle not exceeding . ( A . F . Sidorenko)