section_path: Measuring angles/Units
section_name: Units
paragraph_text: Units
  
  Throughout history, angles have been measured in various units. These are known as angular units, with the most contemporary units being the degree (°), the radian (rad), and the gradian (grad), though many others have been used throughout history. Most units of angular measurement are defined such that one turn (i.e., the angle subtended by the circumference of a circle at its centre) is equal to n units, for some whole number n. Two exceptions are the radian (and its decimal submultiples) and the diameter part.
  
  In the International System of Quantities, an angle is defined as a dimensionless quantity, and in particular, the radian unit is dimensionless. This convention impacts how angles are treated in dimensional analysis.
  
  The following table lists some units used to represent angles.