Arc Length Calculator
Calculate the arc length of a circle from its radius and central angle in degrees.
Circle Arc Length Mathematics
Arc length calculator computes the length of a circular arc from its radius and central angle in degrees.
Arc length is the fraction of a circle's circumference swept out by the central angle. Since a full circle (360°, or 2π radians) has circumference 2πr, any angle θ (in radians) sweeps out a proportional arc length of r × θ.
- 1Enter the circle's radius (r).
- 2Enter the central angle (θ) in degrees.
- 3View the arc length, computed as r times the angle in radians.
A circular arc has a radius of 10 units and spans a central angle of 60°.
Frequently Asked Questions (FAQ)
The formula L = rθ only works when θ is measured in radians, because a radian is defined as the angle that produces an arc length exactly equal to the radius — this makes the relationship a simple direct proportion.
A full circle is 2π radians, so its arc length equals r × 2π — which is exactly the circumference formula, C = 2πr.
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