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 the interior angle of a 15-gon (a pentadecagon) =
[ (n - 2) * 180 ] / n = [ (15 - 2) * 180 ] / 15 = 156°
+713 
