Let A1 A2 A3 ... A15 be a regular polygon. A rotation centered at $A_4$ with an angle of $\alpha$ takes $A_3$ to $A_5$. Given that $\alpha < 180^\circ$, find $\alpha,$ in degrees.
alpha = the measure of one of the interior angles =
(15 - 2) *180 / 15 = 156°
+1234 
