Here, we will apply the concept of Vertically Opposite angle property and central angle property ;
So here, as b is vertically opposite to the angle whose measure is 20° . So , b will also be 20°
And, if we see the angle c, so angle vertically opposite to c will also be c, and as central angle is of 360° , so ;
[tex]{:\implies \quad \sf c+c+20^{\circ}+20^{\circ}=360^{\circ}}[/tex]
[tex]{:\implies \quad \sf 2c+40^{\circ}=360^{\circ}}[/tex]
[tex]{:\implies \quad \sf 2c=360^{\circ}-40^{\circ}}[/tex]
[tex]{:\implies \quad \sf 2c=320^{\circ}}[/tex]
[tex]{:\implies \quad \sf c=\dfrac{320^{\circ}}{2}=160^{\circ}}[/tex]
Hence, we can conclude that ;
- [tex]{\bf{c=160^{\circ}}}[/tex]
- [tex]{\bf{b=20^{\circ}}}[/tex]
