Right angle and straight angle

Suppose we have a map with North, South, East, West Map

If we move from

We have rotated ‘right angle’ in clockwise direction.

We see that

  We have rotated 1/4 of the full turn.

  So, right angle is 1/4 of the full rotation

If we go from

  East to South

We have rotated right angle in clockwise direction

Now, if we go from

  South to North clockwise

We have rotated 1/2 revolutions.

This is straight angle .

  2 right  angle = 1 straight angle

Similarly,

  If we go from East to West Clockwise

Then we have rotated 1/2 revolution

  i.e.  we have rotated

    1 straight angle

Suppose,

  We go from North to North

In this case,

  we have rotated 1 revolution

  ∴  we have rotated 1 full angle

In Summary