Geometry & Trigonometry
Basic

Arc Length (Radians)

Arc length from radius and central angle in radians.

Formula

s=rθs = r\theta

Variables

rRadius
\thetaAngle (rad)

Example

r=2, \theta=π: s=2π

Did You Know?

Measuring angles in radians makes arc length simply radius times angle — one reason radians dominate higher mathematics.

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