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Area of a Circle

A circle is defined as a closed curve. It is said to be the path of a point moving at a constant distance from a particular fixed point. This distance is called radius and this point is known as center of the circle. Here, we shall discuss about area of circle.
Circle is a two-dimensional figure. Area of a circular object is defined as the measurement of space occupied by it.

 Related Calculators Area Calculator Circle

Units of Area of Circle

Area is measured in square unit or unit square or $(unit)^{2}$.

For example, square meter or $m^{2}$, square centimeter or $cm^{2}$. The smaller measurement of area can be square milimeter or $mm^{2}$ and larger measurement of area can be are and hectare.

Formula Related to Area of Circle

The
formula for calculating area is given below:
A = $\pi r^{2}$

Where, $A$ = Area of circle and $r$ = Radius

We know that radius is half the diameter. If d denotes diameter of the circle, then we have $r$ = $\frac{d}{2}$

Substituting this value in the above formula of area, we get

A = $\pi$ $(\frac{d}{2})^{2}$

A = $\frac{\pi d^{2}}{4}$
One can even find radius of circle when its area is given, by performing little transformation in the formula of area:
r = $\sqrt{\frac{A}{\pi}}$

Example:

1)  Find the area of circle with radius equal to 6.5 inch using $\pi$ = 3.14.

Solution:
Formula for area
of circle is,

A = $\pi r^{2}$

Substitute the values of radius and $\pi$, we get

A = $3.14 \times (6.5)^{2}$

= 3.14 $\times$ 42.25

=
132.67 square inch.

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