AIME I 2009 #11
Posted: Sat Mar 28, 2009 9:40 amConsider the set of all triangles [unparseable or potentially dangerous latex formula] where [unparseable or potentially dangerous latex formula] is the origin and [unparseable or potentially dangerous latex formula] and [unparseable or potentially dangerous latex formula] are distinct points in the plane with nonnegative integer coordinates [unparseable or potentially dangerous latex formula] such that [unparseable or potentially dangerous latex formula] Find the number of such distinct triangles whose area is a positive integer.