A | B |

acute angle | measures less than 90 |

right angle | measures 90 degrees |

obtuse angle | measures more than 90, less than 180 |

congruent | has equal measure |

midpoint | divides segment into two equal parts |

angle bisector | divides angle into two equal angles |

acute triangle | has all 3 acute angles |

obtuse triangle | has one obtuse angle |

right triangle | has one right angle |

scalene triangle | has no equal sides |

isosceles triangle | has two equal sides |

equilateral triangle | has all three equal sides |

equiangular triangle | has all three equal angles1 |

complementary angles | two angles that add up to 90 |

supplementary angles | two angles that add up to 180 |

adjacent angles | two angles next to each other |

linear pair | two angles that form a line |

vertical angles | angles formed by intersecting lines |

perpendicular lines | lines that form right angles |

perpendicular bisector | forms right angles and cuts into two equal parts |

parallel lines | coplanar lines that do not intersect |

skew lines | noncoplanar lines |

alternate interior angles | angles on alternate sides of a transversal inside parallel lines - congruent |

alternate exterior angles | angles on alternate sides of transversal, outside parallel lines - congruent |

corresponding angles | angles in same position of "hub" formed by transversal and parallel lines - congruent |

same side interior angles | angles on same side of transversal, inside parallel lines - supplementary |