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 Now fold the circle into eighthsand cut along the folds.(Fig 11.35 (ii))
 Arrange the separate pieces as shown, in Fig 11.36, which is roughly a
parallelogram.

 As done above if we divide the circle in 64 sectors, and arrange these sectors.
It gives nearly a rectangle (Fig 11.37).

 The breadth of this rectangle is the radius of the circle, i.e., ‘r’.
 As the whole circle is divided into 64 sectors and on each side we have 32
sectors, the length of the rectangle is the length of the 32 sectors, which is
half of the circumference. (Fig 11.37)
 Area of the circle = Area of rectangle thus formed

= l × b
= (Half of circumference) × radius

2πr
= ( ) x r
2

= π x r 2