For a p/q star polygon, the interior angle is given by 180°(p-2q)/p.

For your 9/2 star polygon, the interior angle is 180°(9-2*2)/9 = 20°(9-4) =

For your 9/2 star polygon, the interior angle is 180°(9-2*2)/9 = 20°(9-4) =

**100°**.