For number 7:
a) The sum of the adjacent angles is 180. Because if its any three angles thats half of the angles all together 3/6 = 180/360.
b) The sum of the angles in the center is 360 degrees. Because 60 x 6 = 360.
c) The unknown angles (center angles) are 61.25 degrees.
For number 8 (bonus):
It's C) 90 Degrees, because it's a right angle.
Hope this helps :)
12. I assume 
denotes the complement of A, so
Then by definition of conditional probability,
13. By inclusion/exclusion,
To compare these fractions, bring them to the same denominator. Expand the fractions to bring them to the common denominator (LCM):
7/8 = (2 * 7) / (2 * 8) = 14/16
13/16 = (1 * 13) / (1 * 16) = 13/16
Same denominator fractions sorted ascending:
13/16 < 14/16
Initial fractions in ascending order:
13/16 < 7/8
