Развернутый угол равен 180°.
30° = 30/180 = 1/6
45° = 45/180 = 1/4
60° = 60/180 = 1/3
90° = 90/180 = 1/2
120° = 120/180 = 2/3
135° = 135/180 = 3/4
150° = 150/180 = 5/6