Education Technology

Coordinate Geometry - Circles

Subject Area
Math: Geometry: Circles
Level
6-8
Activity Time
60 Minutes
Software
TI Connect™
TI Calculator
TI-83 Plus Family
TI-84 Plus
TI-84 Plus Silver Edition
Other Materials
    The following equipment is required for this activity:
  • TI-Presenter™

  • LCD Projector
  • Two screens
Resource Types
Lessons

Coordinate Geometry - Circles

Activity Overview

In this activity, students investigate the relationship between the coordinates of a point on the circle, radius of a circle, and the values in the equation of the circle.

Before the Activity

Install the Cabri® Jr. App on the students' graphing calculators using one of these two methods:

  • TI-Connect™,  a TI Connectivity Cable, and the Unit-to-Unit Link Cable
  • TI-Navigator™  "send to class" feature
  • See the attached PDF file for detailed instructions for this activity
  • Print pages 1 - 10 from the attached PDF file for your class
  • During the Activity

    Distribute the pages to the class.

    Follow the Activity procedures:

  • Draw a circle of any radius in quadrant 1
  • Drag the circle so that the center of the circle is at the origin
  • Display the coordinates of point P, where the circle intersects the x-axis
  • Display the coordinates of the center and the equation of the circle
  • Notice that the x-value of P represents the radius of the circle
  • Drag point P along the x-axis and relate the equation of the circle to the coordinates of point P
  • Move the center of the circle away from the origin
  • Observe the coordinates of the center and point P
  • Observe how the values relate to the equation of the circle
  • After the Activity

    Review student results:

  • As a class, discuss questions that appeared to be more challenging
  • Re-teach concepts as necessary
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    Subject Area
    Math: Geometry: Circles
    Level
    6-8
    Activity Time
    60 Minutes
    Software
    TI Connect™
    TI Calculator
    TI-83 Plus Family
    TI-84 Plus
    TI-84 Plus Silver Edition
    Other Materials
      The following equipment is required for this activity:
    • TI-Presenter™

    • LCD Projector
    • Two screens
    Resource Types
    Lessons
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