Skip to content / Đến nội dung
ThichHocToan.com

MathNet 2018-part-06 — 181 problems (EN–VI) Question 33

Math Olympiad Vault · MathNet 2018-part-06 — 181 problems (EN–VI)

Question 33

Let $\triangle ABC$ be an acute triangle with pairwise distinct side lengths, and let $O$, $H$ be its circumcenter and orthocenter, respectively.
The line $OA$ meets the altitude of $\triangle ABC$ through $B$ and the altitude through $C$ at the points $P$, $Q$, respectively.
Prove that the circumcenter of triangle $PQH$ lies on one of the medians of triangle $ABC$.

(Note: in a triangle, the segment joining a vertex to the midpoint of the opposite side is called a median.)