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radian (Radian)

SI plane angle measure. Symbol: rad. It is the angle of a circle subtended by an arc equal in length to the circle's radius. Another definition is: the plane angle between two radii of a circle which cut off on the circumference an arc equal in length to the radius. Radian = m/m = 1.

Ontology

SUMO / UNITS-OF-MEASURE

Class(es)

systeme international unit
is instance of
  radian  

Superclass(es)

[tree]
entity
is subclass of
  abstract  
is subclass of
  quantity  
is subclass of
  physical quantity  
is subclass of
  constant quantity  
is subclass of
  angle measure  
is subclass of
  plane angle measure  
is subclass of
  radian  

Coordinate term(s)

ampere  angular degree  becquerel  candela  celsius degree  coulomb  farad  gram  gray  henry  hertz  joule  kelvin degree  lumen  lux  meter  mole  newton  ohm  pascal  second duration  siemens  sievert  steradian  tesla  volt  watt  weber 

Related WordNet synsets

radian, rad
the unit of plane angle adopted under the System International d'Unites; equal to the angle at the center of a circle subtended by an arc equal in length to the radius (approximately 57.295 degrees)
radian is kind of (all)...   radian is kind of...   parts of radian...  

Axioms (1)

If number is an instance of real number, then "number angular degree(s)" is equal to ""number*"pi/"" radian(s)". 
(=>
      (instance ?NUMBER RealNumber)
      (equal
            (MeasureFn ?NUMBER AngularDegree)
            (MeasureFn
                  (MultiplicationFn
                        ?NUMBER
                        (DivisionFn Pi 180))
                  Radian)))