Circle Calculator
Provide any one value to calculate the rest
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Circle Calculator
Enter any one value below to calculate the remaining properties of a circle: radius (R), diameter (D), circumference (C), and area (A).
๐งฎ Input Values
๐ Results
Radius (R)
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Diameter (D)
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Circumference (C)
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Area (A)
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Given
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ฯ (Pi)
3.141592653589793
Formulas Used
D = 2R, C = 2ฯR, A = ฯRยฒ
Notes
Enter any single value to compute the others. If multiple values are provided, the first non-empty field in the order R, D, C, A will be used.
๐ Understanding Circles
Parts of a Circle
- Center: Equidistant from all points on the circle
- Radius: Half of the diameter
- Diameter: Longest distance across the circle
- Circumference: Perimeter of the circle
More Terms
- Arc: Portion of the circumference
- Chord: Segment joining two points on the circle
- Secant: Line intersecting the circle at two points
- Tangent: Touches the circle at exactly one point
Formulas
D = 2R, C = 2ฯR, A = ฯRยฒ
ฯ โ 3.14159, irrational and transcendental.
Further Reading
In history, many attempted to โsquare the circle,โ constructing a square with the same area as a given circle using only compass and straightedge. Lindemann proved ฯ is transcendental in 1880, making this impossible.