Types of Angles Based on MeasurementAcute Angle. Any angle that is less than 90° is an acute angle. ... Right Angle. If the angle formed between two rays is exactly 90° then it is called a right angle or a 90° angle. ... Obtuse Angle. ... Straight Angle. ... Reflex Angle. ... Full Rotation Angle. ... Positive Angles. ... Negative Angles.