Answer:
8 * pi or about 25.13274123
Step-by-step explanation:
The inscribed angle = 1/2 the intercepted arc
40 = 1/2 ( arc CD)
Multiply each side by 2
2 * 40 = 2* 1/2 ( arc CD)
80 = arc CD
To find the length
We find the circumference of the circle
C = 2 * pi *r
C = 2 *pi *18 = 36 pi
Take the fraction of a circle the arc is
80/360 = 2/9
Multiply the circumference by the fraction
2/9* 36 pi
8 pi
If we approximate pi
8 * pi=25.13274123
