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IMO 2019 — Complete Shortlist Question 22

IMO Shortlist · IMO 2019 — Complete Shortlist

Question 22

Let $I$ be the incentre of acute-angled triangle $A B C$. Let the incircle meet $B C, C A$,

and $A B$ at $D, E$, and $F$, respectively. Let line $E F$ intersect the circumcircle of the triangle at $P$ and $Q$, such that $F$ lies between $E$ and $P$. Prove that $\angle D P A+\angle A Q D=\angle Q I P$.