Education Technology

Drawing a Line Tangent to a Circle

Activity Overview

Students use the drawing and measurement tools of Cabri™ Jr. to draw a line tangent to a circle. NCTM Geometry Standard covered: Analyze characteristics and properties of 2- and 3-dimensional geometric shapes and develop mathematical arguments about geometric relationships.

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
  • See the attached PDF file for detailed instructions for this activity
  • Print page 40 from the attached PDF file for your class
  • During the Activity

    Distribute the page to your class.

    Follow the Activity procedures:

  • Draw a circle
  • Draw a radius of the circle
  • Construct a line perpendicular to the radius at its endpoint
  • This will be a tangent line
  • Change the size of the circle and observe the tangent
  • After the Activity

    Review student results:

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