Room for ChanceWhat it measures and where it is used
Plane angle describes rotation or the opening between two directions. A radian relates arc length to radius and is a dimensionless SI derived unit. Degrees retain a much older 360-part division of the circle. A full turn is 360 degrees or 2π radians.
- Classification
- SI derived quantity
- SI unit
- rad
- Dimension
- 1
L: length; M: mass; T: time; Θ: temperature; N: amount of substance. The dimension symbol N is not the unit symbol for newton.
How it works
The calculation first converts to a common reference unit, then to the destination unit. Factors in the table show the reference value for one unit.
Example
180 ° ≈ 3.14159265359 rad
Available units
Reference unit: rad
| Available units | Reference factor |
|---|---|
| ° | 0.0174532925199 × x |
| rad | 1 × x |
| gon | 0.0157079632679 × x |
| turn | 6.28318530718 × x |
| arcmin | 0.000290888208666 × x |
| arcsec | 0.0000048481368111 × x |
Units, history and conventions
The International System of Units (SI) received its name in 1960. Since the 2019 revision, its definitions use fixed values of seven defining constants. SI base and derived quantities should not be confused with the different units used to express them.