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Calculate circle properties from any known value. Find radius, diameter, circumference, area, arc length, and sector area instantly.
A circle is a plane curve consisting of all points at a fixed distance (the radius) from a center point. Key properties include diameter (2r), circumference (2πr), and area (πr²).
Radius
5
Diameter
10
Circumference
31.415927
Area
78.539816
Arc Length
7.8539816
Sector Area
19.634954
| Radius | Circumference | Area |
|---|---|---|
| 1 | 6.28 | 3.14 |
| 2 | 12.57 | 12.57 |
| 5 | 31.42 | 78.54 |
| 10 | 62.83 | 314.16 |
| 25 | 157.08 | 1963.50 |
| 50 | 314.16 | 7853.98 |
Formula
A = πr² | C = 2πr | Arc = (θ/360) × 2πrA = Area of the circle
C = Circumference (perimeter) of the circle
r = Radius — distance from center to edge
θ = Central angle in degrees for arc/sector calculations
Worked Example
Circle with radius = 7
Did you know? The ratio of a circle's circumference to its diameter (π) has been calculated to over 100 trillion digits as of 2024 (source: University of Applied Sciences of the Grisons).
Sources
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