POLYGONS DEFINITION TYPES AND PROPERTIES

SCHOOL: TOTAL CHILD SCHOOL, RIVERS STATE

CLASS: SS1 

TERM: SECOND TERM 

SUBJECT: TECHNICAL DRAWING

WEEK ONE

TOPIC: POLYGONS

• Definition
• Types of Polygons
• Construction of different polygons 

What is a Polygon? 

A polygon is a plane figure with five or more straight sides. A polygon can either be regular 

or irregular A polygon is said to be regular it all its sides are equal and its angles are equal. 

An irregular polygon has unequal sides.

Types of Regular Polygons 

1. Pentagon: A pentagon is a polygon with five sides.
2. Hexagon: A hexagon is a polygon with six sides
3. Heptagon: A heptagon is a polygon with seven sides
4. Octagon:  An octagon is a polygon with eight sides
5. Nonagon: A nonagon is a polygon with nine sides.  

6. Decagon:  A decagon is a polygon with ten sides.

    

   General Properties of All Polygons

   1. They are closed shapes: A polygon must start and end at the same point.

   2. They have straight sides: All sides of a polygon are straight lines.

   3.They have vertices (corners): Where two sides meet, a vertex is formed.

   4. They have interior angles: Every corner of a polygon has an angle inside the shape.

   5. They do not cross each other: The sides must not overlap or cross.

    

   Key Formulas for Polygons

   If a polygon has n sides:

   1. Sum of interior angles = (n - 2) *180

   2. Each interior angle of a regular polygon = (n - 2) *180/n

   3. Sum of exterior angles = Always equals 360°

    

EVALUATION

1. What is a polygon?
2. Explain different types of Polygons.
3. General Properties of all Polygons
4. Three Key Formulas for Polygons