whats the question? if there no question we cant help you.
1/3 because reciprocal is the opposite
You probably jsut need to use law of cosines in order to solve for angle A

or
First seat = 9
second seat = 9 + 6 = 15
third seat = 15 + 6 = 21
fourth seat = 21 + 6 = 27
fifth seat = 27 + 6 = 33
sixth seat = 33 + 6 = 39