Skip to content / Đến nội dung
ThichHocToan.com

MathNet 2018-part-05 — 181 problems (EN–VI) Question 132

Math Olympiad Vault · MathNet 2018-part-05 — 181 problems (EN–VI)

Question 132

Let $T$ be the centroid of triangle $ABC$ and $D$ the midpoint of side $BC$. Let the lines $AT$, $BT$ and $CT$ meet the circumcircle of triangle $ABC$ again at the points $P$, $Q$ and $R$, respectively. Suppose that $|AD|=\frac{\sqrt{3}}{2}|AC|$. Prove that triangle $PQR$ is isosceles.