How it’s calculated
The radian is the SI unit of plane angle: the angle subtending an arc equal to the radius. A full circle is 2π rad = 360° = 400 gon = 1 turn.
Example: 90° × π / 180 = π/2 ≈ 1.5708 rad = 100 gon = 0.25 turn.
Frequently asked questions
How do I convert degrees to radians?
Multiply by π/180 (about 0.0174533). For example, 45° = π/4 ≈ 0.7854 rad.
How many degrees is one radian?
180/π ≈ 57.2958°.
How do I convert decimal degrees to degrees, minutes and seconds?
The whole number is degrees; multiply the fraction by 60 for minutes, and the remaining fraction by 60 for seconds. 12.5125° = 12° 30′ 45″.
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Sources
- The International System of Units (SI Brochure) — BIPM
- NIST Guide to the SI, Appendix B: Conversion Factors (SP 811) — U.S. National Institute of Standards and Technology
Formulas are taken from the free public references above. Results are provided “as is” for informational and educational purposes only. See our disclaimer.
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