Consider a notebook and look at the angle made by the adjacent sides.

The adjacent sides OB and OA of the notebook form an angle AOB. This angle is a right angle.

Similarly, the sides of the alphabet ‘L’ form a right angle. Let us look at this video to learn more about right angles, straight angles, and complete angles.

Suppose you are facing North. You turn around making a complete revolution such that you again face North. The angle you turned by is a complete angle. Try the same for different directions and you will obtain the same results.

Now consider the hour and minute hands of a clock when the time is 8’o clock as shown in the figure below.