This website contains problems from math contests. Problems and corresponding tags were obtained from the Art of Problem Solving website.

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Found problems: 2

2024 Belarusian National Olympiad, 11.8
Tags: space , combinatorial geometry , geometry
Projector emits rays in space. Consider all acute angles between the rays. It is known that no matter what ray we remove, the number of acute angles decreases by exactly $2$ What is the maximal number of rays the projector can emit? [i]M. Karpuk, E. Barabanov[/i]

1982 Bundeswettbewerb Mathematik, 2
Tags: triangle , equilateral , projection , space , geometry
Decide whether every triangle $ABC$ in space can be orthogonally projected onto a plane such that the projection is an equilateral triangle $A'B'C'$.