Yes 720 is the angle sum of a hexagon.
A hexagon cannot have a sum. There can be the sum of its interior angles, its exterior angles, its side lengths, its area (and that of some other area), or other characteristics, but not of a hexagon.
The perimeter of a hexagon is the sum of its 6 sides
The sum of a regular hexagon's interior angles should be 720o and the sum of a regular hexagon's exterior angles should be 360o.
The perimeter of a 6 sided hexagon is the sum of its sides
It has 6 sides.
Sum it is 116 ft