Provide one known value to calculate the remaining values of a circle.
Related
Use our Radius of a Circle Calculator to determine the distance from the center of a circle to any point on its circumference. The calculator can also compute related properties such as diameter, area, and circumference.
Follow these steps:
The radius is a fundamental measure in geometry:
"The distance from the center of a circle to any point on its boundary."

Formula:
Diameter: D = 2r
Radius: r = D / 2

Formula:
Area: A = πr²
Radius: r = √(A / π)

Formula:
Circumference: C = 2πr
Radius: r = C / (2π)

Formula:
Sector Area: A = (θ / 360°) × πr²
Radius: r = √(A × 360 / (θ × π))

Question: Find the radius of a circle with an area of A = 78 m².
Use the formula: r = √(A / π)
Substitute values: r² = 78 / 3.14
r² = 24.840
r = √24.840
r ≈ 4.98 m
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