radian
radplane angle · International · Modern
Radian is the coherent SI unit of plane angle.
Converter
plane angle · International · Modern
degree (angle)
°exact
- Record
- M431
- Definition quality
- Standardized
- Conversion mode
- multiplicative
- Calculator
- Fully calculable
Etymology/person-name origin not separately researched unless stated by standards history; current definition/conversion resolved.
Definition
Non-SI unit accepted for use with the SI; 1° = π/180 rad.
Reference value
One degree (angle) is equal to 0.017453293 radians.
History & use
Degree, arcminute, and arcsecond are retained because of their widespread practical use and are accepted for use with the SI.
Modern use
Widely used for plane angle in navigation, surveying, mapping, geometry, and everyday contexts.
Did you know?
A full turn is 360°, exactly 2π radians.
Sources & evidence
Source tier Tier A · confidence High