The length of arc AB is 9.12 mm:
We first calculate for the radius r of the circle using the equation 
 r = c/(2 sin[theta/2]) 
 where c is the length of chord AB that is given as 9 millimeters
 angle given is 32 degrees
To convert theta 32 degrees into radians: 
 32 degrees * (pi/180) = 32 degrees * (3.14/180) = 0.5583 radians
We now substitute the values into the equation to find the radius r: 
 r = 9/(2 sin[0.5583/2]) 
 r = 16.33 mm
.
We can finally solve for the length s of arc: 
 s = r theta = 16.33 * 0.5583 = 9.12 mm