angle ABC is inscribed in a circle as shown.
What is the measure, in degrees, of angle ABC?

Answer
Find out the measure, in degrees, of angle ABC .
To prove
The relationship between inscribed angles and their arcs
The measure of an inscribed angle is half the measure the intercepted arc.
The formula is
[tex]Measure\ of\ inscribed\ angle = \frac{1}{2}\times measure\ of\ intercepted\ arc[/tex]
As given in the diagram
The measure of the intercepted arc A to B is 120°.
Put value in the formula
[tex]\angle ABC = \frac{1\times 120^{\circ}}{2}[/tex]
∠ABC = 60°
Therefore the measure of the ∠ABC is 60° .