good polygons (3 conditions given)
Source: North Macedonian Mathematical Olympiad 1996 p4
February 12, 2020
geometrycombinatorial geometrypolygonparallel
Problem Statement
A polygon is called good if it satisfies the following conditions:
(i) All its angles are in or in ,
(ii) It is not self-intersecing,
(iii) For any three sides, two are parallel and equal.
Find all for which there exists a good -gon.