In a regular polygon, if the ratio of the interior and exterior angle is 3 : 1, then find the difference between the interior and exterior angle of the polygon.
Calculate the number of sides of a regular polygon, if :
(i) its interior angle is five times its exterior angle.
(ii) the ratio between its exterior angle and interior angle is 2 : 7.
(iii) its exterior angle exceeds its interior angle by 60o.