Welcome! Here you will learn how to determine the relationships between measures of
angles (interior and exterior) and the number of different polygons.
Below are the angle amounts for figures that have threesides to twelvesides:
Name of Figure  Interior Angles Add Up To...  Exterior Angles Add Up To... 
Triangle (three sides)  180 Degrees(°)  360°
 Quadrilateral (four sides)  360°  360° 
Pentagon (five sides)  540°  360° 
Hexagon (six sides)  720°  360° 
Septagon (seven sides)  900°  360° 
Octagon (eight sides)  1080°  360° 
Nonagon (nine sides)  1260°  360° 
Decagon (ten sides)  1440°  360° 
Hendecagon (eleven sides)  1620°  360° 
Dodecagon (twelve sides)  1800°  360° 
Want to know how to find the sum of the angles of the interior angles of any polygon?
Formulas and Examples For Polygons
