In the figure, BC is a chord and CD is a tangent through the point C. If ∠AOC = 138°, then find ∠ACD.
Answer & explanation
Correct answer: option 2
∠ABC = \(\frac{∠AOC}{2}\) = \(\frac{138}{2}\) = 69°
Angle formed on center is double the angle formed on circumference by same arc.
∠ABC = ∠ACD = 69°
(alternate segment theorem)