# Gradian

## Unit of measurement of an angle, equal to 1/400th of a circle / From Wikipedia, the free encyclopedia

#### Dear Wikiwand AI, let's keep it short by simply answering these key questions:

Can you list the top facts and stats about Grad (angle)?

Summarize this article for a 10 year old

In trigonometry, the **gradian** – also known as the **gon** (from Ancient Greek * *γωνία* ( gōnía)* 'angle'),

**grad**, or

**grade**

^{[1]}– is a unit of measurement of an angle, defined as one-hundredth of the right angle; in other words, 100 gradians is equal to 90 degrees.

^{[2]}

^{[3]}

^{[4]}It is equivalent to 1/400 of a turn,

^{[5]}9/10 of a degree, or π/200 of a radian. Measuring angles in gradians is said to employ the

*centesimal*system of angular measurement, initiated as part of metrication and decimalisation efforts.

^{[6]}

^{[7]}

^{[8]}

^{[Note 1]}

**Quick Facts**gon, General information ...

gon | |
---|---|

General information | |

Unit of | Angle |

Symbol | gon, ᵍ, grad |

Conversions | |

1 gon in ... | ... is equal to ... |

turns | 1/400 turn |

radians | π/200 rad ≈ 0.0157... rad |

milliradians | 5π mrad ≈ 15.71... mrad |

degrees | 9/10° |

minutes of arc | 54′ |

In continental Europe, the French word * centigrade*, also known as

*centesimal minute of arc*, was in use for one hundredth of a grade; similarly, the

*centesimal second of arc*was defined as one hundredth of a centesimal arc-minute, analogous to decimal time and the sexagesimal minutes and seconds of arc.

^{[12]}The chance of confusion was one reason for the adoption of the term

*Celsius*to replace

*centigrade*as the name of the temperature scale.

^{[13]}

^{[14]}

Gradians are principally used in surveying (especially in Europe),^{[15]}^{[7]}^{[16]}
and to a lesser extent in mining^{[17]} and geology.^{[18]}^{[19]}

The gon is officially a legal unit of measurement in the European Union^{[20]}^{: 9 } and in Switzerland.^{[21]} However, the gradian is not part of the International System of Units (SI).^{[22]}^{[20]}^{: 9–10 }