Angle Measurement
An angle is a figure formed by two rays with a common endpoint. The two rays are called the sides of the angle and the common endpoint is called the vertex of the angle.
A protractor is used to measure an angle in degrees (symbol: °).
A right angle is an angle whose measure is 90°.
An acute angle is an angle whose measure is less than 90°.
An obtuse angle is an angle whose measure is greater than 90° and less than 180°.
Learn more about angle measurement by reading the explanation below.
Practice: Answer the following exercises about angle measurement.