IMO Shortlist 1977 problem 4
Dodao/la:
arhiva2. travnja 2012. Describe all closed bounded figures
in the plane any two points of which are connectable by a semicircle lying in
.
%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