How many sides do these regular polygons have if their interior angles are
30 18 40 36 12 Degrees
The "formula" for computing an interior angle of any regular polygon is given by :
(n - 2)*180 / n
Unfortunately......no regular polygons have the measures you have indicated......an equilateral triangle has the smallest degree measure for any interior angle = 60. All regular polygons with more sides have larger angles at each vertex.