# Geometry Formulas

rename
Updated
2008-05-29 00:18

## Triangles

Question | Answer |
---|---|

three interior angles = | 180 degrees |

exterior angles | the adjacent angle which is formed by extending one side of the triangle |

remote interior angles | the two non-agjacent angles opposite the exterior angle |

relationship of exterior angles to the remote interior angles | exterior angles = sum of remote |

relationship of side legnth to the angle size | longest side opposite longest angle; shortest angle opposite shortest angle |

triangle inequality | the sum of the legnths of a triangle must be greater than the legnth of the third side |

base angles of an isosceles | in an isocales triangle base angles are equal in measure |

midsegment | the segment joining the midpoints of two sides of a triangle |

triangle midsegment relations | midsegment of a triangle is parallel to the third side of a triangle; a triangle midsegment is one-half the length of the third side |

congruence | all sides are equal in length and all corresponding angles are equal in measure = + ~ |

congruent triangles | SSS, SAS, ASA, AAS |

(SSS) | three sides of a triangle are congruent to three corresponding sides of a triangle |

(SAS) | two sides of a triangle and the angle included between the two sides are congruent to two corresponding sides and the included angle of another triangle |

(ASA) | two angles of a triangle and the side included between the two angles are congruent to two corresponding angles and the included side of another triangle |

(AAS) | the two angles of a triangle and the side not included between the two angles are congruent to two corresponding angles and the non-included side of another triangle |

(AAA) | not a congruence pattern |

(SSA) | not a congruence pattern |

CPCTC | corresponding parts of congruent triangles are congruent; the definition of congruence |