IMO Shortlist 1977 problem 4
Dodao/la:
arhiva2. travnja 2012. Describe all closed bounded figures
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in the plane any two points of which are connectable by a semicircle lying in
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.
%V0
Describe all closed bounded figures $\Phi$ in the plane any two points of which are connectable by a semicircle lying in $\Phi$.
Izvor: Međunarodna matematička olimpijada, shortlist 1977