MathDB
IMO Shortlist 2009 - Problem G5

Source:

July 5, 2010
geometryparallelogramgeometric inequalityareapolygonIMO Shortlist

Problem Statement

Let PP be a polygon that is convex and symmetric to some point OO. Prove that for some parallelogram RR satisfying PRP\subset R we have RP2\frac{|R|}{|P|}\leq \sqrt 2 where R|R| and P|P| denote the area of the sets RR and PP, respectively.
Proposed by Witold Szczechla, Poland