MathNet 2019-part-07 — 184 problems (EN–VI) Question 164

Let $\overline{S T}$ be a chord of a circle $\omega$ which is not a diameter, and let $A$ be a fixed point on $\overline{S T}$. For which point $X$ on minor arc $\widehat{S T}$ is the length $A X$ minimized?