Answer:
Explanation:
Let O be a circle. Draw diameters of the circle with no of diameters as large as possible such that the circle is divided into equal sectors.
Cut each sector and paste on a paper with one showing point edge down and other sector adjacent to first showing point edge up. Like this we get a trapezium with just one sector left out in our hand. Cut it into half and paste on either end to get a perfect rectangle.
Now we have the rectangle having side as r, and length = a value pi times the radius.
Since the length x2 have to give the circumference because of our activity, we get
circumference = 2pir
Area of circle = area of all sectors =
area of rectangle = length xwidth
=pir (r) = pir^2