If a convex polygon truncates an inner angle and the sum of the inner angles of another polygon is 1620 degrees, then the number of sides of the original polygon is?

If a convex polygon truncates an inner angle and the sum of the inner angles of another polygon is 1620 degrees, then the number of sides of the original polygon is?

The sum of inner angles of n-polygon is (n-2) * 180 degrees,