IMO Shortlist 1987 problem 13
Dodao/la: arhiva2. travnja 2012.
Is it possible to put
points in the Euclidean plane such that the distance between each pair of points is irrational and each three points determine a non-degenerate triangle with rational area? (IMO Problem 5)
Proposed by Germany, DR
Izvor: Međunarodna matematička olimpijada, shortlist 1987