MathNet 2022-part-01 — 197 problems (EN–VI) Question 9

Let $ABCDEFGHI$ be a regular 9-gon with its vertices labelled anticlockwise, and let $ABJKLM$ be a regular hexagon with its vertices also labelled anticlockwise. Prove that the angles $\angle HMG$ and $\angle KEL$ are equal.