Answer:
18 sides
Step-by-step explanation:
Since it's a regular polygon, all the interior angles are equal, so they're all 160 degrees.
The sum of the interior angles of a polygon is 180*(n-2). Each angle is the total over n, in this case 160 degrees.
160 = 180*(n-2)/n
160n = 180n - 360
-20n = -360
n = 18 sides
