Skip to content / Đến nội dung
ThichHocToan.com

MathNet 2009-part-03 — 175 problems (EN–VI) Question 101

Math Olympiad Vault · MathNet 2009-part-03 — 175 problems (EN–VI)

Question 101

Let $\omega$ be a circle in the plane and $A,B$ two points lying on it. We denote by $M$ the midpoint of $AB$ and let $P \neq M$ be a new point on $AB$. Build circles $\gamma$ and $\delta$ tangent to $AB$ at $P$ and to $\omega$ at $C$, respectively $D$. Consider $E$ to be the point diametrically opposed to $D$ in $\omega$. Prove that the circumcenter of $\triangle BMC$ lies on the line $BE$.
Flavian Georgescu