If
you look at a clock and the time is 3:15, what is the angle between the
hour and the minute hands? ( The answer to this is not zero!)
The time is 3:15, i.e. 25% of the time between 3 and 4
has passed. The hour-hand should, by simple mechanical logic, have moved
25% of its total distance between 3 and 4.
The total angle the hand covers is 360%, so the angle covered between 3 and 4 should be 360/12 = 30 degrees.
The
minute hand is smack on 3, and the hour hand is a quarter of 30 degrees
further on. The angle made between them is thus 30*1/4 = 7.5 degrees.