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
As given in the diagram
The measure of the intercepted arc A to B is 120°.
Put value in the formula
∠ABC = 60°
Therefore the measure of the ∠ABC is 60° .
Let us observe the given figure,
When two lines intersect each other, the angles opposite to each other are Vertically Opposite Angles. Vertically opposite angles are always equal in measure.
As, we can observe that the given lines intersect each other, and they form vertically opposite angles as and
Therefore,
Substituting the given measures of the angles, we get
So, x =
Since, the measure of angle POR =
=
=
Therefore, the measure of angle POR is 49 degrees.
