# List of Notes - Category: Ratios and Proportions

## Ratios

A ratio is a comparison of two numbers by division.

The ratio of m to n can be expressed in the following ways:

• m to n
• m:n
• m/n

Last expression tells us, that ratio is, actually, a fraction.

## Proportions

An equation, stating that two ratios are equal is called a proportion.

For example, 5/3=10/6 is a proportion.

Example 1. Determine, whether the ratios 18/4 and 27/6 form a proportion.

Let's reduce first ratio: 18/4=(9*color(red)(2))/(2*color(red)(2))=9/2.

## Solving Percent Problems

Basically, there are 3 types of percent problems:

• What is p% of m?
• p% of what is m?
• What percent of m is n?

Now, we will practice in these percent problems.

These types of problems can be easily solved using proportions.