Use the formula for a circle: Arc Length = r × θ
Make sure θ is in radians
If θ is in degrees, convert it to radians first: radians = degrees × π / 180
Identify the radius r
Multiply the radius by the central angle in radians
For a full circle, use Arc Length = 2πr
For a fraction of a circle, use Arc Length = (θ / 360) × 2πr when θ is in degrees
For a curve on a graph, use Arc Length = ∫ from a to b of √(1 + (dy/dx)²) dx
For a parametric curve, use Arc Length = ∫ from a to b of √((dx/dt)² + (dy/dt)²) dt
For a polar curve, use Arc Length = ∫ from α to β of √(r² + (dr/dθ)²) dθ