Arc Length Calculator

| Added in Math & Numbers

Arc length is the distance measured along the curved portion of a circle. This calculator determines the arc length using the radius and central angle, accepting both degrees and radians.

Formula

The arc length is calculated as:

[\text{Arc Length} = r \times \theta]

Where:

  • r is the radius of the circle
  • θ (theta) is the central angle in radians

Converting Degrees to Radians

If your angle is in degrees, convert it first:

[\text{Radians} = \text{Degrees} \times \frac{\pi}{180}]

Calculation Example

For a circular pathway with radius 5 meters and central angle of 60 degrees:

Step 1: Convert to radians
[\text{Radians} = 60 \times \frac{\pi}{180} = 1.047 \text{ radians}]

Step 2: Calculate arc length
[\text{Arc Length} = 5 \times 1.047 = 5.235 \text{ meters}]

Common Arc Lengths

Central Angle Fraction of Circumference Arc Length Formula
360° (2π rad) Full circle 2πr
180° (π rad) Half circle πr
90° (π/2 rad) Quarter circle πr/2
60° (π/3 rad) Sixth of circle πr/3

Applications

  • Architecture: Designing curved structures and arches
  • Engineering: Calculating wheel rotations and gear teeth
  • Road Design: Planning curved highway sections
  • Astronomy: Measuring angular distances in the sky
  • Sports: Analyzing curved ball trajectories

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Frequently Asked Questions

Arc length is the distance along the curved line forming part of a circle. It is the length of a portion of the circumference.

Multiply degrees by π/180. For example, 60 degrees = 60 × (π/180) ≈ 1.047 radians.

Arc length is used in architecture, engineering, road design, wheel rotations, pendulum motion, and any application involving circular motion or curved paths.

The arc length is in the same units as the radius you entered. If radius is in meters, arc length is in meters.

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