An obtuse angle is an angle that measures more than 90 degrees but less than 180 degrees. In other words, it is larger than a right angle and smaller than a straight angle.

An angle is a measure of rotation or turning and is usually measured in degrees or radians. In geometry, an angle is the figure formed by two rays, called the sides of the angle, sharing a common endpoint, called the vertex. The size of an angle is determined by the amount of rotation from one ray to the other.

An acute angle is an angle that measures less than 90 degrees.

Degrees are a unit of measurement for angles, representing the rotation between two rays. The degree angle system divides a full rotation into 360 units called degrees.