what is the coterminal of angle 60?

Answer 1

60 + 360 = 420°

or

60 - 360 = -300°

Beyond that you can continue to add or subtract multiples of 360° for more coterminal angles.

Answer 2

There is no single unqiue coterminal angle (an angle that shares the same rays) for a given angle. You can add or subtract any multiples of 360 degrees to get a new values. So one coterminal angle for 60 degress is 360-60= 300 degrees. Another is 360+60 = 420 degrees, and yet another is 60 + - 360 = -300.