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
**

**
**