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MathNet 2010 — Part 06 Question 44

Math Olympiad Vault · MathNet 2010 — Part 06

Question 44

Let $\triangle ABC$ be an equilateral triangle with the side of $20$ units. Vid divides this triangle into $400$ smaller equilateral triangles with the sides of $1$ unit. Eva then picks $4$ of the vertices of these smaller triangles. The vertices lie inside the triangle $ABC$ and form a parallelogram with sides parallel to the sides of the triangle $ABC$. There are exactly $46$ smaller triangles that have at least one point in common with the sides of this parallelogram. Find all possible values for the area of this parallelogram.

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