# square

A *square* is the regular^{} 4-gon, that is, a quadrilateral^{} whose 4 angles and 4 sides are respectively equal. Each angle of a square must be a right angle^{}.
This implies a square is a parallelogram^{} that is both a rhombus^{} and a rectangle^{} at the same time.

Notice, however, that if a quadrilateral has its 4 sides equal, we cannot generally say it is a square, since it might be a rhombus as well.

If $r$ is the length of a side, the diagonals of a square (which are equal since it’s a rectangle too) have length $r\sqrt{2}$.

Title | square |

Canonical name | Square |

Date of creation | 2013-03-22 12:02:32 |

Last modified on | 2013-03-22 12:02:32 |

Owner | drini (3) |

Last modified by | drini (3) |

Numerical id | 7 |

Author | drini (3) |

Entry type | Definition |

Classification | msc 51-00 |

Related topic | Quadrilateral |

Related topic | Parallelogram |

Related topic | Rectangle |

Related topic | Rhombus |

Related topic | ParallelogramLaw |

Related topic | RegularPolygon |