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MathNet 2015-part-04 — 191 problems (EN–VI) Question 41

Math Olympiad Vault · MathNet 2015-part-04 — 191 problems (EN–VI)

Question 41

Given is an equilateral triangle $ABC$. On the line through $B$ parallel to $AC$ lies a point $D$, such that $D$ and $C$ lie on the same side of line $AB$. The perpendicular bisector of $CD$ intersects line $AB$ in $E$. Prove that triangle $CDE$ is equilateral.