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Circle calculator

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This calculator computes the area, circumference, radius and diameter of a circle. The calculator provides a step-by-step explanation to find the unknown element.

Circle Calculator
Input one element of a circle and select element to find.
help ↓↓ examples ↓↓
Solve for
Enter one element of a circle.
A =
C =
r =
d =
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Circle formulas
Circle illustration showing radius, diameter and area.
$$ A = r^2 \, \times \pi $$
area
$$ C = 2 \, r \, \pi $$
perimeter
$$ d = 2 \, r $$
diameter
Examples
ex 1:
Find the area of the circle with a diameter of 6cm.
ex 2:
Calculate the area of a circle whose circumference is C=6π.
ex 3:
Find the diameter of a circle with an area of A = 9/4πin.
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Circle calculator – Widget Code

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Widget preview: Circle calculator

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