Originally Posted by

**mattio** The circle one.

Each unshaded reason equals x. You know the sum of the two unshaded reasons, 2x, equals the arithmetic mean, or average, of the shaded reasons. The two shaded regions are equal to eachother, as they have the same central angle since they are vertical angles. Thus, the average area of the shaded reagions is the value of each shaded region. **So, each shaded region is equal to 2 unshaded regions, or 2x**. You now have two regions with values of x degrees, and two more regions with values of 2x degrees, altogether for a total of 6x.

6x = 360

x = 60