Education Technology

Investigating Equations of Lines

Published on 10/17/2008

Activity Overview

Students explore the equations of lines written in the form: y = mx + b. They move points defining the lines, and view the related changes in the parameters of the equations.

NCTM Geometry Standard: Specify locations and describe spatial relationships using coordinate geometry and other representational systems.

Before the Activity

  • Install the Cabri™ Jr. App on the students' graphing calculators using TI Connect™, a TI Connectivity Cable, and the Unit-to-Unit Link Cable
  • Set up the TI-Navigator™ system
  • See the attached PDF file for detailed instructions for this activity
  • Print pages 48 - 49 from the attached PDF file for your class
  • During the Activity

    Distribute the pages to your class.

    Follow the Activity procedures:

  • Draw a line and find its equation
  • Move the points defining the line and observe the changes in the equation
  • Draw another line and observe changes in its equation


  • TI-Navigator activity:
  • Have students submit equations with certain characteristics (specific slope, parallel to a given line, with the same y-intercept as a given line)
  • After the Activity

  • Review student results
  • As a class, discuss questions that appeared to be more challenging
  • Re-teach concepts as necessary