The interior angles of a polygon with $n$ sides add up to $(n-2) \times 180°$.
The exterior angles of any polygon always add up to $360°$. For a regular polygon, each exterior angle is $\dfrac{360°}{n}$. Example: a hexagon's interior angles total $(6-2) \times 180° = 720°$.
Remember
- Interior sum $= (n-2)\times 180°$.
- Exterior angles always sum to $360°$.