What is an acute angle?

An acute angle is any angle that is less than 90°, so it is smaller than a right angle. A slightly opened pair of scissors or a narrow slice of pizza shows an acute angle.

Examples

• A 45° angle is acute.
• The angle in a narrow slice of pizza is acute.
• Each angle in an equilateral triangle is 60°, which is acute.

Quick facts

• An acute angle is less than 90°.
• You can remember it as 'a cute little angle'.