This document provides information about calculating the perimeter of a circle. It defines key terms like circle, radius, diameter, and pi. It explains that the perimeter of a circle is calculated by multiplying 2π by the radius (perimeter = 2πr). An example problem calculates the perimeter of a circle with a diameter of 4cm as being 4πcm. It concludes by asking review questions about perimeter, the perimeter formula, and calculating perimeter given a radius.

1. WELCOME

2. Name of college : New B.Ed. College Nellimoodu
Name of student: SUMI S. V.
Option : Mathematics
Register Number: 180/13376012

3. Topic : Perimeter of a circle
Standard : IX
Subject : Mathematics

4. Perimeter of a circle

5. Circle
c
r
Circle is a closed figure. its
radius ‘r’ and the centre ‘c’.

6. Diameter
A c B
AB is the diameter of a circle. The
diameter is twice the radius.

7. Determination of π
π is a constant obtained when
the perimeter of a circle is divided
by its diameter.
Value of π is approximately 3.14

8.  How will you find the perimeter of a circle?
Perimeter of a circle is the length of the
circumference of the circle. In any Circle,
Perimeter of a circle π
Diameter
Perimeter of a circle π
2 x radius

9. Perimeter of a circle = 2πxr
= 2πr

10. PERIMETER OF A CIRCLE
Perimeter of a circle with radius ‘r’
in the product of π and twice the radius
ie, perimeter = 2πr
c r

11. Problem
1. If the Diameter of a circle is 4cm then
find the perimeter of the circle ?
Diameter = 4cm
Radius =4/2 = 2cm
Perimeter of a circle = 2πr
= 2π x 2
= 4πcm

12. Review Questions
1. What is perimeter?
2. What is the formula for the perimeter of a
circle?
3. If radius is 7cm then find the perimeter of
the circle?

13. THANK YOU