What is a proportional relationship?

In this lesson you will learn to how to create proportional relationships by expanding

ratios.

Let’s Review

A ratio is a comparison between two quantities that are related.

A Common Mistake

Since the ratio of pineapples to apples is 2 to 3, there must be just 2 pineapples and three apples.

Core Lesson Ratios express a constant pattern of a relationship

hamburger:

The ratio of buns to patties is 2 : 1.

For every two buns, there is one patty.

Core Lesson

4 : 2 6 : 3

6 : 3 reduces to 2 : 1

4 : 2 reduces to 2 : 1

2 : 1 means a pattern of two buns for every

patty2 : 1

Core Lesson

A ratio can have larger equivalent ratios just like a fraction can have

larger equivalent fractions.

1 : 4x2 x2 2 : 8

In this lesson, you learned how to create proportional

relationships by expanding ratios.

Guided Practice

The ratio of orange to green candy in a bowl is 1 to 2. Draw a picture of how a

bowl with 12 pieces would look.

Extension ActivitiesSelect a different groups of students in your class and record their

liking of the following hobbies. Do any of these ratios have a proportional relationship? If so, which ones?

  : students like sports.

: students like to play video games.  : students like to cook.  : students like to dance.  : students like to sing.  

Quick Quiz

Proportional relationships can be difficult to understand.

Describe what you would say if you were going to explain this concept to a fellow classmate who doesn’t get it.