What is an obtuse angle?

An obtuse angle is greater than 90° but less than 180°, so it is wider than a right angle but not yet a straight line. An open laptop leaning back or a reclining chair makes an obtuse angle.

Examples

• A 120° angle is obtuse.
• The angle of an open laptop leaning back is obtuse.
• 150° is obtuse because it is between 90° and 180°.

Quick facts

• An obtuse angle is between 90° and 180°.
• An angle of exactly 180° is a straight line, not an obtuse angle.