Angle QSR is an inscribed angle and is equal to half the intercepted arc. So if angle QSR = 52 degrees then the arc measures 104 degrees. Source: http://www.1728.org/circangl.htm (Look at the first graphic).
This is because to get to 14/15 you must divide by 6 but when getting to 42/45 you must divide 2. Therefore 14/15 is your answer because the problem went to the most reduced fraction.