Circle

A circle is a simple shape of Euclidean Geometry consisting of those points in a plane which are equidistant from a given point called the center. The common distance of the points of a circle from its center is called its radius.

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Formula to learn circles:

Formula to find Area of the Circle:

-->Area of the circle = ‘pi’ * r² Where, r is the radius of the circle.
Formula to find Diameter of the Circle:
Diameter of circle = 2 * r Where, r is the radius of the circle

Formula to find Circumference of the circle:
Circumference of circle = 2 * ‘pi’ * r (or) ‘pi’ * d Where, r is the radius of the circle and d is the diameter of the circle.
Let us now solve one problem in each of the above.
Problem on Area of Circle.
Find the Area of a circle with radius of 8 cm.

Area of the circle = 'pi' * r²
Here 'pi' is equal to 3.14
= (3.14)*8*8
=(3.14)*64
=200.96
The Area of the circle is 200.96 cm.

Problem on Diameter of a Circle.
Find the Diameter of a circle with radius of 8 cm.

Diameter of the circle = 2*r
=2 * 8
= 16
The Diameter of the circle is 16 cm.

Problem on Circumference of a Circle.

Find the Circumference of a circle with radius of 8 cm.
Circumference of the circle = 2 * 'pi'
= 2 * 3.14
= 6.28
The Circumference of the circle is 6.28 cm.