The sum of the exterior angles of a regular polygon is 360º
Each exterior angle of a regular polygon is 60º/n
360º/n=60º
360/60=n
6=n
A polygon with 6 sides is a hexagon.
Use the formula (n-2)×180
(6-2)*180=4*180=720º
another solution...
you have 6 interior angles (hexagon)
if an exterior angle is 60º, the corresponding interior angle is 180-60=120º
you have 6 of these 120º angles
6*120=720º