triangle ABC is inscribed within a circle and has diameter line AB, with the inscribed angle at C, if the angle meausure of A is 15 degrees, what is the arc measure of AC?
the answer is not 30
The inscribed angle at C is half of the central angle subtended by arc AC. Since the diameter line AB is the same as the radius of the circle, the central angle subtended by arc AC is twice the angle measure of inscribed angle C.
Therefore, the central angle is 2 * 15 = 30 degrees. Since the arc measure is equal to the central angle measure, the arc measure of AC is also 30 degrees.