A | B |

ray | a part of a line having only one endpoint |

point | an exact location in space |

line | a collection of points extending endlessly along a path |

acute angle | 60 degrees, less than 90 degrees |

obtuse angle | 150 degrees, greater than 90 degrees but less than 180 |

right angle | measures exactly 90 degrees |

straight angle | measures exactly 180 degrees |

angle | two rays having a common endpoint called a vertex |

plane | an endless flat surface determined by 3 points not on a line |

line segment | a part of a line having 2 endpoints |

parallel lines | lines in the same plane that never intersect |

perpendicular lines | lines that intersect to form right angles |