Problem 4 of RMO 2006 (Regional Mathematical Olympiad-India)
Source: Combinatorics (Box Principle)
September 13, 2009
geometryrectanglesearchcombinatorics unsolvedcombinatorics
Problem Statement
A square is dissected in to 9 rectangles by lines parallel to its sides such that all these rectangles have integer sides. Prove that there are always two congruent rectangles.