Theorems about Tangents & Chords - play around with each of these applets to discover!

What do you want to download?

You can either download the .ggb file alone or the complete webpage for students with tasks.

I agree to the terms of GeoGebra's non-commercial license

• Offline Activity (.zip)

• GeoGebra Files

  1. Applet 1 (.ggb)
     
  2. The angle where the radius intersects a tangent line is ALWAYS a right angle (90-degrees!). Try moving the center around and see what happens. You can also move the other points, as well! (.ggb)
     
  3. Applet 3 (.ggb)
     
  4. "Party Hat" Theorem: If TWO tangent lines are drawn from the SAME external point (point C, here), then their tangent SEGMENTS will ALWAYS be congruent! (.ggb)
     
  5. If two chords, AB & CD, are equidistant to the center of a circle (i.e. their 'apothems' are the same length), then the chords, themselves, will ALWAYS be congruent! Don't forget to click on (.ggb)
     
  6. The inscribed angles (
     
  7. The inscribed angles (
     
  8. Applet 8 (.ggb)
     
  9. A Deeper Look: If two chords are congruent, then their intercepted arcs are congruent. (.ggb)
     
  10. If a diameter (EF, here) is perpendicular to a chord (CD, here), then it BISECTS the chord AND it's INTERCEPTED ARC (arc CD will also be bisected).! (.ggb)