Sector Area Calculator

Find the area, arc length, and perimeter of a circular sector from its radius and central angle. Works in degrees and radians.

Input

Enter the radius and central angle to compute the sector area, arc length, and perimeter.

Radius r

Central angle

Angle unit

Area

19.634954

Arc length

7.853982

Perimeter

17.853982

Lengths use the same unit as the input, and the area uses that unit squared.

The area of a circular sector with radius r and central angle θ in radians is area = (1/2) × r² × θ.
When the angle is given in degrees, this equals area = π × r² × (degrees ÷ 360).
The arc length equals arc = r × θ where θ is in radians.
The perimeter equals the arc length plus two radii (2r).
The radius must be positive and the central angle must be greater than 0 and at most a full turn (360 degrees or 2π).

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