Given: DR tangent to Circle O.
If m _ RDC = 120°, then m DAC =
•60
•120
•240

Answer:
The measure of the arc DAC is 240°
Step-by-step explanation:
we know that
The semi-inscribed angle is half that of the arc it comprises.
so
m∠RDC=(1/2)[arc DAC]
we have
m∠RDC=120°
substitute
120°=(1/2)[arc DAC]
240°=[arc DAC]
Rewrite
arc DAC=240°
Answer:
Option C.
Step-by-step explanation:
If a tangent and arc intersect at a point on a circle the measure of angle formed by the intersection will be half of the arc intercepted.
Therefore, m∠RDC = [tex]\frac{1}{2}(mDAC)[/tex]
Since m∠RDC = 120°
120 = [tex]\frac{1}{2}(mDAC)[/tex]
m(arcDAC) = 2×120°
m(arcDAC) = 240°
Option C. 240° is the answer.