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Mathematics: All about angles


In this module, you can study how angles are formed, the names of types and parts of angles, and how to measure angles using a protractor.


The video above contains a 10-minute long explanation from Khan academy covering the basics of angles: how they're formed, types of angles, some vocabulary about angles and a little information about degrees. You only need to watch the first six minutes of this video.


The above video shows you how to use a protractor to measure angles.


Did you know?

The number of degrees in an angle is unrelated to the length of its lines.

An angle's size has nothing to do with the direction the angle is facing.

Study and practice


A circle has 360

A straight line is 180

A right angle is 90

An acute angle is less than 90

An obtuse angle is between 90 - 180

i.e. greater than 90 and less than 180

A reflex angle is between 180 - 360

i.e. greater than 180 and less than 360