After a polygon is connected with an angle (the section line can not reach the vertex), the inner angle of the formed polygon is 2520 degrees, so the original polygon has more sides

After a polygon is connected with an angle (the section line can not reach the vertex), the inner angle of the formed polygon is 2520 degrees, so the original polygon has more sides

After a polygon is connected with a corner (the section line can't be more than the vertex), the number of sides is one more side,
Let the number of new polygon sides be n, then (n-2) × 180 ° = 2520 °
The solution is n = 16
So the original number of sides is 16-1 = 15
A: the original number of polygon sides is 15