It's a period of time equal to 45 minutes. ___________________________
Since I posted this answer, crowds of people have complained that I should have said how many degrees, not how many minutes.
The problem is: '3 o,clock' and '3:45' are not angles. They're both times. I knew that right away, as soon as you called the first one ' o'clock '. So right there, I knew that we weren't dealing with angles. The only way I knew to answer the question was in terms of time.
