Right angle: An angle equal to 90 is called a right angle.
Oblique angle: an angle greater than 90 and less than180 is called obtuse angle.
Boxer: An angle equal to 180 is called a boxer.
Excellent angle: more than180 and less than 360 is called excellent angle.
Bad angle: more than 0 and less than 180 is called bad angle, and acute angle, right angle and obtuse angle are all bad angles.
Fillet: An angle equal to 360 is called a fillet.
Negative angle: the angle formed by clockwise rotation is called negative angle.
Positive angle: the angle of counterclockwise rotation is positive angle.
Angle 0: An angle equal to zero.