A protractor is an adjustable tool that typically measures in degrees and radians. It can be used to effectively measure angles and in the construction process to achieve the desired angle.
Protractors can be manual or they can be magnetic. Magnetic protractors have an easy to read dial and an adjustable angle pointer that is ideal for scoring, deep cutting, or other heavy duty applications.
The compass is a separate tool that can also be used to measure angles and lengths.