Answer:
81 degrees
Step-by-step explanation:
The circumference is given by
C = 2*pi*r
20 = 2*pi*r
Divide each side by 2pi
20/2pi = 2*pi*r/2pi
10/pi =r
We know the arc length can be found by
s =r theta where theta is in radians
9/2 = 10/pi *theta
Multiply each side by pi/10 to isolate theta
9/2 * pi/10 = pi/10 *10/pi *theta
9*pi/20 = theta
We need to convert to degrees
9*pi/20 * 180/pi
81 degrees
