# Ratios

- Author:
- Arpit Kesharwani

- Topic:
- Ratios

UNIT 2 • LESSON 3MORE ABOUT CONSTANT OF PROPORTIONALITY

- Setting the Stage
- 3.1: Equal Measures
- 3.2: Centimeters and Millimeters
- Are You Ready For More?
- 3.3: Pittsburgh to Phoenix
- Summary

- Understand that tables of equivalent ratios represent proportional relationships between the two corresponding quantities.
- Understand relationships between rows and between columns in tables of values that represent proportional relationships.
- Understand and use the terms proportional relationship and constant of proportionality.
- Identify the constant of proportionality for a proportional relationship represented by a table.

- Demonstrating that I know what it means for two figures to have the same area.
- Being able to explain how to find the area of a figure that is composed of other shapes.
- Demonstrating that I know how to find the area of a figure by decomposing it and rearranging the parts.

**FAMILY MATERIALS:**To review or build a deeper understanding of the math concepts, skills, and practices in this lesson, visit the Family Materials provided by Illustrative Mathematics Open-Up Resources. (Links to an external site.)Links to an external site.Use the numbers and units from the list to find as many equivalent measurements as you can. For example, you might write “30 minutes is 1212 hour.”You can use the numbers and units more than once.1120.460501212400.01313313300.324151562centimetermeterhourfeetminuteinchThere is a proportional relationship between any length measured in centimeters and the same length measured in millimeters.There are two ways of thinking about this proportional relationship.- If you know the length of something in centimeters, you can calculate its length in millimeters.
- Complete the table.
- What is the constant of proportionality?

- If you know the length of something in millimeters, you can calculate its length in centimeters.
- Complete the table.
- What is the constant of proportionality?

- How are these two constants of proportionality related to each other?
- Complete each sentence:
- To convert from centimeters to millimeters, you can multiply by ________.
- To convert from millimeters to centimeters, you can divide by ________
*or*multiply by ________.