option : c. 2x + 15 = 145
cuz, the angles are vertical opposite angles
Based on these first few terms, we can deduce that the next term is computed by switching the sign of the previous one, and multiplying it by 3: we start with -1, we switch the sign (1) and multiply by 3 (3); then again we switch the sign (-3) and multiply by 3 (-9), and so on.
Since switching sign is the same as multiplying by -1, we can compute every next term by multiplying the previous one by -3:

So, the recursive formula is

because it states precisely that the next term is -3 times the previous one.
The central angle is about 74.8426. Try using the website Omni to help you out. It contains an arc length calculator.
Multiply 42.50 by 3.5 then add 60.00 to your answer