## Directly and Inversely Proportional

Table of Contents

## Directly Proportional

Directly proportional: when one amount increases, another amount increases at the same rate.

The symbol for “directly proportional” is ∝

## Inversely Proportional

Inversely Proportional: when one value increases, at the same rate that the other decreases.

## Examples

Directly Proportional | Inversely Proportional | |

Have more workers | You pay more | Work time is shorter |

How many spending ∝ workers

## Constant of Proportionality

Constant of proportionality is the value that relates two amounts.

can be written as | note | |

spending = 10 x workers | y = kx | where k is Constant of Proportionality |

Work time = 10 / workers | y = k/x | where k is Constant of Proportionality |