Basics of Coordinate Metrology
Learn module 1:  Units - Angles

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To describe the geometric features unambiguously, it is usually necessary to specify, in addition to the base quantity length with its SI unit "meter", also the direction. In metrology, the unit "degree" is used for this.
  • Definition: A degree is the angle starting at the center whose vertex cuts out the 360th part of a circle perimeter.
    • The degree (unit symbol: °) is divided into (angular) minutes and (angular) seconds.
    • 1° = 60' (angular minutes)
    • 1‘ = 60" (angular seconds)
      Note: The degree is a legal unit that does not belong to the SI system of units. The relevant SI unit for the angle is the radian (rad) ( Definition of all SI Units). It is, however, less common in production metrology.
Degree (°) 360° 180° 90° approx. 57° 1°
Radian (rad) 2 /2 1 /180

      

  • Conversion of degrees in radian (please enter degrees and press "="): 

    ° rad

  • Conversion of radian in degrees (please enter radian and press "="): 

    rad °

  • In most cases, the angles are designated by small Greek letters (α, β, γ).
  • The 90° angle is also called "right angle"
  • The angle β is called "supplementary angle", since it supplements the angle α to 90°.
  • The 360° angle corresponds to the 0° angle