Answer :
Step-by-step explanation:
Finding a regular polygon with x amount of sides, you use the equation [tex](x-2)[/tex] to find the amount of triangles. Replace x with 15 and you will get 13. Each triangle has angles that add to [tex]180^{o}[/tex], so you would do 180 * 13 to find the total of all of the interior angles, = 2340. Then, divide 2340 by 15, and you will get 156!