There are 360 degrees in a full turn.

There are 180 degrees in half a turn.

There are 90 degrees in a quarter of a turn. 

Another name for a quarter turn is a 'Right Angle'

Any angle less than 90 degress is called an 'Acute Angle' 

Any angle that is between 90 and 180 degrees is called an 'Obtuse Angle'

 Any angle that is between 180 and 360 degrees is called a 'Reflex Angle'

Triangles

Triangles have three sides. There are many different types of triangles:

Equilateral triangle

• 3 equal sides

• 3 equal angles of 60°

  

Isosceles triangle

• 2 equal sides

• 2 equal angles

Scalene triangle

• No equal sides

• No equal angles

Right-angled triangle

• One of its angles is a right angle (90°)