Skip to content / Đến nội dung
ThichHocToan.com

MathNet 2016-part-01 — 184 problems (EN–VI) Question 86

Math Olympiad Vault · MathNet 2016-part-01 — 184 problems (EN–VI)

Question 86

Let $M$ and $N$ be the midpoints of the sides $AC$ and $AB$, respectively, of an acute triangle $ABC$. Let $\omega_B$ be the circle centered at $M$ passing through $B$, and let $\omega_C$ be the circle centered at $N$ passing through $C$. Let the point $D$ be such that $ABCD$ is an isosceles trapezoid with $AD$ parallel to $BC$. Assume that $\omega_B$ and $\omega_C$ intersect in two distinct points $P$ and $Q$. Show that $D$ lies on $PQ$.