Given:
[tex]m\angle ABC=60[/tex]
To find:
The [tex]m\angle ADC[/tex].
Solution:
In circle B, [tex]\angle ABC[/tex] is central angle and [tex]\angle ADC[/tex] is inscribed angle from two points A and C.
According to central angle theorem, central angle is always twice of inscribed angle.
[tex]m\angle ABC=2(m\angle ADC)[/tex] [Central angle theorem]
[tex]60=2(m\angle ADC)[/tex]
Divide both sides by 2.
[tex]\dfrac{60}{2}=m\angle ADC[/tex]
[tex]30=m\angle ADC[/tex]
Therefore, [tex]m\angle ADC=30[/tex].
