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MathNet 2019-part-08 — 179 problems (EN–VI) Question 98

Math Olympiad Vault · MathNet 2019-part-08 — 179 problems (EN–VI)

Question 98

A regular hexagon $A B C D E F$ has side length 1 and center $O$. Parabolas $P_{1}, P_{2}, \ldots, P_{6}$ are constructed with common focus $O$ and directrices $A B, B C, C D, D E, E F, F A$ respectively. Let $\chi$ be the set of all distinct points on the plane that lie on at least two of the six parabolas. Compute
$$
\sum_{X \in \chi}|O X|
$$
(Recall that the focus is the point and the directrix is the line such that the parabola is the locus of points that are equidistant from the focus and the directrix.)