4.1 Polygons

4.1 Polygons
4.1.1 Regular Polygons
1.  A regular polygon is a polygon where
(a) all its sides are of equal length, and
(b) all its interior angles are of equal size.

2. The number of axis of symmetry of a regular polygon is equal to its number of sides.


4.1.2 Exterior and Interior Angles of Polygons
1. The exterior and interior angles at a vertex of a polygon is supplementary.

2. The sum of interior angles of an n-sided polygon is  ( n 2 ) × 180 o  

Each interior angle of a regular n-sided polygon is
( n 2 ) × 180 o n

The sum of all exterior angles of a polygon is 360o.

5. Each exterior angle of a regular n-sided polygon is 
360 o n

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