Math Calculators ▶ Radius of a Circle Calculator
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Our radius of a circle calculator mainly functions to find the radius of a circle from the values of circumference, area, or diameter.
Truly uttering, our calculator is pretty easy to use if you stick to the following usage guide!
Input:
Output:
You all may be familiar with a circle, a well-known and widely used geometrical figure.
“The distance from the center of a circle to any of its points on the circumference is known as the radius”
In geometry, a circle is defined by many related entities. And if you are willing to find its radius given different parameters, then these include:
As we know that:
\(Diameter=D=2*r\)
or
\(r=\dfrac{D}{2}\)
You know that:
\(Area=A=𝜋r^{2}\)
or
\(r^{2}=\dfrac{A}{𝜋})
As you know that:
\(C=2*𝜋*r\)
or
(r=\dfrac{C}{2𝜋}\)
You know that:
\(A=\dfrac{\theta}{360^\text{o}}*𝜋*r^{2}\)
or
\(r=sqrt{\dfrac{A*360^\text{o}}{\theta*𝜋}}\)
Let us resolve an example that may help you in finding radius of a circle:
What’s the radius of a circle having area as \(78m^{2}\)?
\(r^{2}=\dfrac{A}{𝜋}\)
\(r^{2}=\dfrac{78}{3.14}\)
\(r^{2}=24.840\)
\(r=\sqrt{24.840}\)
\(r=4.983\)
From the source of Wikipedia: Radius, Formula, Use in coordinate systems
From the source of Khan Academy: Radius, diameter, circumference & π, Labeling, Area of parts of circles
From the source of Lumen Learning: Circles, Equation of a Circle in Standard Form, General form of a circle