Question

Find the number of angles in the given figure.[ 3 marks]

Answer 1

An angle is made up of two rays starting from a common initial point called vertex.

In the figure above, O is the vertex.
Angles shown in the figure are

1. $\angle AOB$ = ${40}^{\circ }$ (0.5 marks)

2. $\angle BOC$ = ${20}^{\circ }$ (0.5 marks)

3. $\angle COD$ = ${30}^{\circ }$ (0.5 marks)

4. $\angle AOB$ + $\angle BOC$ = ${40}^{\circ }$+ ${20}^{\circ }$ = ${60}^{\circ }$ (0.5 marks)

5. $\angle AOB$ + $\angle BOC$ + $\angle COD$ = ${40}^{\circ }$ + ${20}^{\circ }$ + ${30}^{\circ }$ = ${90}^{\circ }$ (0.5 marks)

6. $\angle BOC$ + $\angle COD$ = ${20}^{\circ }$ + ${30}^{\circ }$ = ${50}^{\circ }$ (0.5 marks)

Therefore, there are 6 angles.