Answer:
The length of arc AC is

Explanation:
step 1
Find the circumference of the circle
The circumference is equal to

we have

substitute


step 2
Find the length of arc AC
Remember that the circumference subtends a central angle of 360 degrees
The measure of arc AC is equal to
arc AC+30°=180° ----> because the diameter divide the circle into two equal parts
arc AC=180°-30°=150°
using proportion
