Find the reflex angle between the two hands of the clock shown.

The clock shows 9:12. Hour hand: $30\times 9+\frac{12}{2}=276^{\circ }$; minute hand: $6\times 12=72^{\circ }$. The hands differ by $204^{\circ }$, which is already more than $180^{\circ }$, so the reflex angle is $204^{\circ }$ (the smaller angle is $156^{\circ }$).