Right angles, acute and obtuse angles

​​In a nutshell

Angles are measured in degrees ($$\degree$$). A right angle measures 90$$\degree$$, and can be used to describe turns.

Right angles and turns

A right angle measures 90$$\degree$$. You can measure angles with a protractor. A right angle can also be described as a quarter of a turn. 

If you turn around once fully, you will have turned 360$$\degree$$. Therefore:

• 1 right angle makes a quarter turn.
• 2 right angles make a half-turn.
• 3 right angles make three quarters of a turn.
• 4 right angles make a full turn.

​Note: A half-turn (180$$\degree$$) is also called an "angle on a straight line".

​​​​Other angles

Apart from right angles, there are other angles to consider:

Acute angles are less than 90$$\degree$$:

Obtuse angles are greater than 90$$\degree$$ but less than 180$$\degree$$:

Reflex angles are more than 180$$\degree$$ but less than 360$$\degree$$:

Here are all the angles together: