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MathNet 2014 Question 14

Math Olympiad Vault · MathNet 2014

Question 14

Consider a regular $n$-gon with $n\gt 3$, and call a line acceptable if it passes through the interior of this $n$-gon. Draw $m$ different acceptable lines, so that the $n$-gon is divided into several smaller polygons.

a. Prove that there exists an $m$, depending only on $n$, such that any collection of $m$ acceptable lines results in one of the smaller polygons having 3 or 4 sides.

b. Find the smallest possible $m$ which guarantees that at least one of the smaller polygons will have 3 or 4 sides.

Question illustration

Supplemental illustration; no additional hypothesis is imposed.