# Constant of Proportionality Review

### Assessment is Tomorrow!!!!!! Tomorrow means Wednesday!!!!!!

## Definition

The constant of proportionality is the constant ratio found in a proportional relationship. The constant of proportionality and unit rate (which we learned about back in January) are actually the same thing. We

**find the constant of proportionality by taking the**__always__*y*value and dividing it by the*x*value whether it's in a table or a graph.## Proportional or not?

If you are looking at a table or graph, there has to be a constant for it to form a proportional relationship. You have to get the same number every time when you take *y* and divide it by *x*. If you don't get the same number, then it is not proportional.

We can also look at a graph and tell if it forms a proportional relationship. The graph of a proportional relationship has to form a straight line ** and** it also has to go through the origin, which is the point (0,0) on a graph. The picture above shows a line that forms a proportional relationship.

## These are the same two videos as last time. Watch them again before moving on. The two videos are only 5 minutes total.

Finding Constant of Proportionality in a Table

8-R3-03: Determining proportionality and constant of proportion from a graph.