Diagonals of a n-gon - Iran NMO 2008 - Problem1
Source:
September 22, 2010
combinatorics unsolvedcombinatorics
Problem Statement
In how many ways, can we draw diagonals of a -gon with equal sides and equal angles such that:
none of them intersect each other in the polygonal.
each of the produced triangles has at least one common side with the polygonal.