A | B |

ray | A part of a line that starts at an endpoint and goes on forever in one direction. |

angle | a figure formed by to rays with a common endpoint, called a vertex. |

vertex | the common endpoint of two rays that form an angle. |

degree | a unit of measurement that is 1/360 of a complete turn. |

right angle | an angle that has a measure of 90 degrees. |

straight angle | an angle that has a measure of 180 degrees. |

acute angle | an angle that has a measure that is greater than 0 degrees, but less than 90 degrees. |

obtuse angle | an angle that has a measure that is greater than 90 degrees, but less than 180 degrees. |

supplementary angles | 2 angles who's measure, if added equals exactly exactly 180 degrees. |

complimentary angles | 2 angles who's measure, if added equals exactly 90 degrees. |