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MathNet 2008-part-01 — 165 problems (EN–VI) Question 26

Math Olympiad Vault · MathNet 2008-part-01 — 165 problems (EN–VI)

Question 26

Let $ABC$ be a triangle and $X$, $Y$, $Z$ points on the sides $BC$, $AC$, $AB$ respectively. Let $A'$, $B'$, $C'$ be the circumcenters of the triangles $AZY$, $BXZ$, $CYX$ respectively. Prove that
$$
(A'B'C') \geq \frac{(ABC)}{4}
$$