Mensuration and Circle

Read about circles

Circumference

The circumference of a circle with radius r is 2πr. As the diameter d of a circle is 2r. So, circumference is πd. the simplified value of π is 22/7.

Area

The area of a circle with radius r is πr2.

Ring

The ring forms two concentric circles. Two or more circles with the same center are called concentric circles.

ring
The radius of the outer circle is r1 and the radius of the inner circle is r2.
The area of the ring formed = (πr12 - πr22)
= π(r12 - r22)


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