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Radius, chord and arc calculator
The central angle selects the arc being measured. For angles over 180°, the sagitta describes the selected major arc, not the minor segment. Keep the radius and output lengths in one common unit.
Formula and inputs
Arc length = Rθ in radians; chord = 2R sin(θ/2); sagitta = R(1 − cos(θ/2)).
Worked example
A 50 mm radius and 60° central angle give a 50 mm chord, 52.360 mm arc and 6.699 mm sagitta.
Use the result in your setup
Confirm the input dimensions and unit system against your drawing before calculating. Keep full precision during a calculation and round only the final value to suit the measurement or programming requirement. A numerical result does not account for a machine’s complete setup, workholding or control configuration.