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# Chapter 1

### Ratio and Proportional Reasoning

Term | Definition |
---|---|

Rate | A ratio that compares two quantities with different kinds of units Ex: boys to girls, dollars to pounds, miles per hour |

Unit Rate | when a rate is simplified so it has a denominator of one unit ex: $24/6bottles = $4 per bottle or $4/1 bottle |

Complex fractions | fractions with a numerator, denominator or both that are also fractions |

Dimensional Analysis | the process of including the units of measure as factors when you compute |

Proportional | if two quantities have a constant ratio or unit rate |

Non-proportional | two quantities where the relationship is not constant |

Equivalent ratios | ratios that have the same value ex: 4/10 = 12/30 = 2/5 |

Coordinate plane | a type of grid that is formed when two number lines intersect at their zero points. |

Quadrants | The four regions formed when the number lines intersect at their zero points |

Ordered pair | a pair of numbers used to locate or graph points on the coordinate plane ex: (3, -2) |

Proportion | an equation stating that two ratios or rates are equivalent. |

rate of change | a rate that describes how one quantity changes in relation to another |

constant rate of change (slope) | if the rate of change between any two quantities is the same (m = change in y over change in x) |

slope (constant rate of change) | the constant rate of change (m = change in y/change in x) |

Direct Variation (pre-algebra only) | when two variable quantities have a constant ratio |

Constant of Variation (constant of proportionality) - pre-algebra only | the constant ratio y=kx The "k" is the constant of proportionality or constant of variation |

similar figures - pre-algebra only | two polygons where their corresponding angles are congruent and their corresponding sides are proportional |

scale - pre-algebra only | determined by the ratio of a given length on a drawing or model to its corresponding actual length |

scale factor - pre-algebra only | a scale written as a ratio without units in simplest form |

indirect measurement - pre-algebra only | when distances or lengths are difficult to measure directly you use the properties of similar polygons and proportions |