Circumference of a Circle

The distance covered by travelling once around a circle is called Circumference of a Circle.

^{Circumference of a Circle}⁄_Diameter    = π(pie)

^{Circumference of a Circle}⁄_2r               = π(pie)

Circumference of a Circle = 2πr

• The great Indian athematician Aryabhatta (A.D. 476 – 550) gave an approximate value of π (pie). 

• He stated that π = ⁶²⁸³²⁄₂₀₀₀₀, which is nearly equal to 3.1416.

• π (pie) is an irrational number.

• Its decimal expansion is Non-terminating and Non-recurring (Non-repeating). 

• However, for practical purposes, we generally take the value of π (pie) as = ²²⁄₇ or 3.14, approximately.

Q. Calculate the circumference of a circle having radius 7 m.

 Ans: 

The circumference here can be calculated using the formula,

         Circumference = 2πr 

                           C  = 2 × π × 7

                               = 2 × ²²⁄₇ × 7

                               = 44 m.