How many right angles do you make if you start facing
(a) south and turn clockwise to west?
(b) north and turn anti–clockwise to east?
(c) west and turn to west?
(d) south and turn to north?

To do :

We have to find the number of right angles we make in each case.

Solution :

We know that,

1 revolution $= 360^o$

Therefore,

(a) If we start facing south and turn clockwise to west, we will turn $90^o$ from the starting point.

This implies,

Number of right angles $=\frac{90^o}{90^o}$

$=1$ 

(b) If we start facing north and turn anti-clockwise to east, we will turn $270^o$ from the starting point.

This implies,

Number of right angles $=\frac{270^o}{90^o}$

$=3$ 

(c) If we start facing west and turn to west, we will turn $360^o$ from the starting point.

This implies,

Number of right angles $=\frac{360^o}{90^o}$

$=4$ 

(d) If we start facing south and turn to north, we will turn $180^o$ from the starting point.

This implies,

Number of right angles $=\frac{180^o}{90^o}$

$=2$