Inverse proportion is the relationship between two variables when their product is equal to a constant value. When the value of one variable increases, the other decreases, so their product is unchanged.

y is inversely proportional to x when the equation takes the form:

y = k/x

or

xy = k

where k is a constant

In contrast, directly proportional variables increase or decrease with each other.

### Inversely Proportional Examples

- Speed and travel time are inversely proportional. The faster you go, the less time it takes to complete your trip.
- The volume of an ideal gas is inversely proportional to the pressure of the gas (Boyle's Law)