Problem

Source: Kyiv City MO 2022 Round 1, Problem 8.3

Tags: geometry



In triangle $ABC$ $\angle B > 90^\circ$. Tangents to this circle in points $A$ and $B$ meet at point $P$, and the line passing through $B$ perpendicular to $BC$ meets the line $AC$ at point $K$. Prove that $PA = PK$. (Proposed by Danylo Khilko)