Answer
22.5$^{\circ}$
Work Step by Step
1. 360$^{\circ}$/12 = 30$^{\circ}$ degrees in one hour
2. At 9:45 the minute and hour hand are very close. A minute hand is on 9. An hour hand is already 45/60 passed from 9 to 10 hour.
Therefore (3/4)$\times$30$^{\circ}$ = 22.5 $^{\circ}$
