Welcome to Planet Infinity KHMS

01 October, 2007

area of a circle

Dear students ,
Watch this video and do the activity.


To find the area of a circle of given radius by paper folding,cutting and pasting.

Material Required
Coloured Paper
Pair of scissors
Geometry Box

Step 1 Cut a circle of given radius from the coloured paper.
Step 2 Divide the circle into 16 equal parts by paper folding.
Step 3 Cut 16 parts and arrange them to form a parallelogram.
Step 4 Take the last cutout and again divide it into 2 equal parts.
Step 5 Arrange the 2 parts and the shape in step 3 so that a rectangle is formed.
Step 6 Measure the length & breadth of the rectangle & calculate its area.

We observe that the cutouts of the circle are arranged to form a rectangle.
The length of the rectangle is equal to half of the circumference of the circle and breadth of the rectangle is equal to the radius of the circle.
The area of the circle is calculated using the formula of area of the rectangle.

Length of Rectangle =____________________
Breadth of Rectangle=___________________
Area of Rectangle = ___________________

So, the Area of Circle = _________________


Anonymous said...

Hello,I am Vishal jain of class
9th-g,roll no.50.I had great experience in planet infinity,my maths lab.it is an activity by which we are able to visualize the concept of finding the area of circle of given radius by paper folding and cutting.I liked this activity.In maths lab we do lots of fun by doing these activities.I love this way of learning maths.


Anonymous said...

Hello, our names are Rodrigo Gutierrez and Barbara Rojas, we are from Chili, and we are students of pedagogy in mathematics in the University Católica del Maule. In these days we have been discussing blog, wanted to say that we found very interesting you blog and the methodology used to teach, very interactive and easy to understand. The way you explain the area of the circle we do not know her and we found very good and above all how it works. Thank you very much for leaving open space for everyone and thank you for considering our comments and also for the delivery of material in order to improve the teaching of mathematics.

Anonymous said...

thank you very much for helping in my maths project

ekta said...

it is very helpful for my project.so,thank you

Anonymous said...


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