# Activities

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TI-Nspire™ CAS

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Connecting Ratios to Equations

#### Activity Overview

This activity allows students to reason about ratio tables, which helps their understanding of what a ratio describes in a context and what quantities in equivalent ratios have in common.

#### About the Lesson

This TI-Nspire™ lesson allows students to understand that a proportional relationship is a collection of equivalent ratios. A collection of equivalent ratios, cA:cB, for any positive number c, can be graphed in the coordinate plane using the coordinates (cA, cB). The graph represents a proportional relationship and lies on a ray with the endpoint at the origin. This activity focuses on the fact that a proportional relationship can be described by an equation of the form y = kx, where k is a positive constant, often called a constant of proportionality.

Prior to working on this lesson, students should understand:

• how to plot points in a coordinate grid by associating a ratio with an ordered pair of values;
• how to generate a table of proportional relationships.

This is Lesson 10 out of 15 in the Building Concepts in Mathematics: Ratios and Proportional Relationships Series