Question

8. In the diagram, the measure of the arc from A to B not

passing through C is 80 degrees. What is the measure of
angle ACB?
A. 20 degrees
B. 40 degrees
C. 80 degrees
D. 160 degrees

Answer 1

Explanation:

for the same arc, the angle at the circumference of the circle is half of the angle at the center of the circle.

and the arc angle is normally representing the angle at the center of the circle.

therefore, the

angle ACB = arc angle AB / 2 = 80/2 = 40°

so, B is the right answer.