WHY must a hexagon add up to 720° (in pictures)
Because there are now 4 triangles in a pentagon, it must add up to `4times180°=720°`.
The hexagon can be made from 4 triangles.
An equilateral hexagon will have 6 equal internal angles and would be
Each internal angle is 120°.
But the interior angles would still add up to 720°.