MathNet 2024-part-06 — 165 problems (EN–VI) Question 52

Let $A_{1} A_{2} \ldots A_{19}$ be a regular nonadecagon. Lines $A_{1} A_{5}$ and $A_{3} A_{4}$ meet at $X$. Compute $\angle A_{7} X A_{5}$.
Proposed by: Nithid Anchaleenukoon