Answer:
Step-by-step explanation:
Something along the lines of this...
The central angle corresponding to AOB is half of the 8pi/9 radians mentioned, meaning that the central angle of AOB is 4pi/9.
Converting that to degrees:
4pi/9 180 degrees
-------- * -------------------- = 80 degrees.
1 pi
I think the answer is 4/12 or 1/3