An angle measures how far something has turned and it is measured in
degrees, which are symbolised with a little o sign after the number. We can
measure angles using an object called a protractor.
A full turn (coming back to the where you started from) is 360o.
A right angle is 90o and is one quarter of a full turn.
An angle which is less than a right angle (less than 90o) is called an acute
An angle which is more than a right angle but less than a straight line. (more
than 90o but less than 180o) is called an obtuse angle.
An angle which is greater than 180o is called a reflex angle.
All of the angles inside a triangle will always add up to 180o.