Question 884694
a + 360/n = 180.  a is the size of the interior angles of the regular polygon, and n is the number of sides.<P>
160 + 360/n = 180<P>
360/n = 20<P>
n = 360/20 = 18 sides.<P>
The sum of interior angles is 18 * 160 = 2880 degrees.