Constant of Proportionality Activity

**Example 1:** This graph shows how the distance Marcela runs depends on the number of track practices she attends.

**Example 2:** This graph shows how the cost of a corporate team-building event depends on the number of attendees.

Practices, x |
Distance in miles, y |
yx = k |

1 | 2 | 21 = ? |

2 | 4 | 42 = ? |

3 | 6 | 63 = ? |

4 | 8 | 84 = ? |

5 | 10 | 105 = ? |

What is the constant of proportionality, *k*?

*Write your answer as a decimal or integer.*

Number of attendees, x |
Cost in dollars, y |
yx = k |

2 | 1 | 12 = ? |

4 | 2 | 24 = ? |

6 | 3 | 36 = ? |

8 | 4 | 48 = ? |

10 | 5 | 510 = ? |

What is the constant of proportionality, *k*?