Given:
A circle is centered on point B.
Points A, C and D lie on its circumference.
If measures 40°.
To find:
The .
Solution:
Central angle theorem: According to this theorem, the central angle is equal to the twice of inscribed angle on the same intercepted arc.
In the given figure is the central angle and
is the inscribed angle on the same arc AC.
Using central angle theorem, we get
Therefore, the measure of angle ADC is 20°.