A circle of radius is given. A collection of triangles is called good, if the following conditions hold:
(i) each triangle from is inscribed in ;
(ii) no two triangles from have a common interior point.
Determine all positive real numbers such that, for each positive integer there exist a good collection of triangles, each of perimeter greater than .
Solution
1. See IMO-2018 Shortlist, Problem G3.
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