Since a whole revolution has 360º, when we have an angle bigger than 360º the angles start to repeat.
We can subtract 360º to the given angle to find the coterminal angle. In this case:
[tex]540º-360º=180º[/tex]
And from an reference angle of 0º, this is exactly a half revolution. Thus, the angle is in the x axis, and it's coterminal angle is 180º
