This document is a student paper submitted by Jesna Joseph for a mathematics education course. It provides definitions and properties of polygons, including that a polygon is a closed geometric figure formed by three or more straight lines. Specific polygons are named, such as triangles, quadrilaterals, pentagons, and hexagons. Formulas are given for calculating the sum of interior angles and exterior angles of polygons based on the number of sides. An example problem is worked out for a polygon with 12 sides.

2. SREE NARAYANA TRAINING COLLEGE
SREEKANDESWARAM , CHERTHALA,
POOCHAKKAL
KERALA UNIVERSITY
B.Ed 2014-2015

3. PAPER IX
THEORETICAL BASES OF
MATHEMATICS EDUCATION II

4. SUBMITTED BY,
NAME : JESNA JOSEPH
OPTION : MATHEMATICS
REG NO : 18014383002

5. SUBMITTED TO,
Mrs. GEETHA . P
Lecturer in Mathematics
S N T C, Poochakkal

6. STANDARD : IX
UNIT : POLYGONS
TOPIC : PROPERTIES OF POLYGONS

7. POLYGONS
A closed geometrical figure formed
by three or more straight lines is called a
polygon.

8. SOME POLYGONS AND THEIR NAMES
TRIANGLE
QUADRILATERAL

9. PENTAGON

10. HEXAGON

11. A polygon with seven sides and angles is called a hectagon.
A polygon with eight sides and angles is called an
Octagon.
A polygon with nine sides and angles is called a Nanagon.

12. ANGLES OF A POLYGON
 The sum of angles of a polygon with ‘n’
sides is ( n-2 ) x 1800
 The sum of exterior angles of a polygon is 3600

13. Consider a polygon with 12 sides.
a) Find the sum of interior angles of the polygon.
b) What about the sum of exterior angles of the polygon.

14. Solution:
No of sides = 12
a) Sum of interior angles = ( n-2 ) x 1800
= ( 12-2 ) x 1800
= 18000
b) Sum of exterior angles = 3600

15. THANK YOU