__POLYGONS__The word polygon means having many sides. Therefore a closed plane figure made up of several line segments that are joined together is called a polygon.

For example, a triangle, a quadrilateral are polygons.

**NB**. A circle is not a polygon as it is not made of line segments.

**The number of diagonals in a polygon of sides n is n(n-3)/2**

__Diagonals:__

**Types of polygons**Regular polygons: A polygons having all angles and all sides are equal is called a regular polygon.

Irregular polygons: A polygon may have unequal angles and sides. Such polygons are called irregular polygon.

__Name of polygons according to their sides____Name__

__Number of sides__

Triangle 3

Quadrilateral 4

Pentagon 5

Hexagon 6

Heptagon 7

Octagon 8

Nonagon 9

Decagon 10

__Types of angle of a polygon__

**Interior Angle:**angle formed by two adjacent sides inside the polygon.

__Sum of Interior Angles in a Regular Polygon of Sides n is:__**(n-2) × 180 degree**

Exterior Angle: angle formed by two adjacent sides outside the polygon.

__Sum of Exterior Angles in a Regular Polygon of Sides n is:__

**360 degree**

..................................❤.....................................