closed recticular polygon
Source: China TST 1987, problem 2
May 16, 2005
analytic geometrygeometryinductiongeometry unsolvedPolygonscoordinatesChina
Problem Statement
A closed recticular polygon with 100 sides (may be concave) is given such that it's vertices have integer coordinates, it's sides are parallel to the axis and all it's sides have odd length. Prove that it's area is odd.