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USAJMO 2023 Question 2

USAJMO · USAJMO 2023

Question 2

In an acute triangle $ABC$, let $M$ be the midpoint of $\overline{BC}$.
Let $P$ be the foot of the perpendicular from $C$ to $AM$.
Suppose that the circumcircle of triangle $ABP$
intersects line $BC$ at two distinct points $B$ and $Q$.
Let $N$ be the midpoint of $\overline{AQ}$.
Prove that $NB = NC$.

Proposed by Holden Mui. One nonofficial editorial point; manual essay grading.