Understanding Ratio Basics

What is a Ratio?

A ratio is a way to compare two or more quantities. It shows how many times one quantity is contained within another.

For example, if there are 2 apples and 3 oranges, the ratio of apples to oranges is 2:3.

How to Write Ratios

• Ratios can be written in three different ways: using the colon symbol (2:3), as a fraction ($\frac{2}{3}$), or with the word "to" (2 to 3).

Simplifying Ratios

Just like fractions, ratios can be simplified by dividing both terms by their greatest common divisor (GCD).

Using Ratios in Real Life

• Ratios are used in cooking to maintain the correct proportions of ingredients.
• They are also used in maps to represent scale, like 1 cm on the map equals 10 km in real life.

Examples

Example 1: Ratio of Boys to Girls

In a class, there are 15 boys and 10 girls. What is the ratio of boys to girls?

Solution: The ratio of boys to girls is 15:10. Simplifying by dividing both terms by 5 gives 3:2.

Example 2: Ratio of Red to Blue Marbles

You have 6 red marbles and 9 blue marbles. What is the ratio of red to blue marbles?

Solution: The ratio is 6:9. Simplifying by dividing both terms by 3 gives 2:3.