# Geometry Symbols

## Table of symbols in geometry:

Symbol | Symbol Name | Meaning / definition | Example |
---|---|---|---|

∠ | angle | formed by two rays | ∠ABC = 30° |

measured angle | ABC = 30° | ||

spherical angle | AOB = 30° | ||

∟ | right angle | = 90° | α = 90° |

° | degree | 1 turn = 360° | α = 60° |

deg | degree | 1 turn = 360deg | α = 60deg |

′ | prime | arcminute, 1° = 60′ | α = 60°59′ |

″ | double prime | arcsecond, 1′ = 60″ | α = 60°59′59″ |

line | infinite line | ||

AB | line segment | line from point A to point B | |

ray | line that start from point A | ||

arc | arc from point A to point B | = 60° | |

| |
perpendicular | perpendicular lines (90° angle) | AC | BC |

| | | parallel | parallel lines | AB || CD |

≅ | congruent to | equivalence of geometric shapes and size | ∆ABC ≅ ∆XYZ |

~ | similarity | same shapes, not same size | ∆ABC ~ ∆XYZ |

Δ | triangle | triangle shape | ΔABC ≅ ΔBCD |

|x-y| |
distance | distance between points x and y | | x-y | = 5 |

π | pi constant |
π = 3.141592654...
is the ratio between the circumference and diameter of a circle |
c = π·d = 2·π·r |

rad | radians | radians angle unit | 360° = 2π rad |

^{c} |
radians | radians angle unit | 360° = 2π ^{c} |

grad | gradians / gons | grads angle unit | 360° = 400 grad |

^{g} |
gradians / gons | grads angle unit | 360° = 400 ^{g} |