# Lesson 2: Proportions

In this lesson you will learn about proportions, their importance, how to set them up and how to solve them.

A proportion is an equivalent relationship of quantities.

We often use proportions to convert to or from percentages.

For example, what is 10% of 45?

We can set up a proportion: 45 corresponds to 100%, then what corresponds to 10%?

10 : 100 = n : 45

n = (45 x 10)/100

Additional practice will help you master the skills. Below is a note and more math practice on the topic.

PhET Interactive Simulations

University of Colorado Boulder

https://phet.colorado.edu