Search

Outline

  1. Nine-point Circle
    1. Nine-point Circle (Part 1)
    2. Nine-point Circle (Part 2)
    3. Nine-point Circle (Part 3)
    4. Nine-point Circle (Part 4)
    5. Feuerbach's Theorem
    6. 16 Points of Tangency

Nine-point Circle

Author:Alex CHIK
Topic:Circle
script of a talk by Mr. C.K. Leung on 25/4/2015 cover picture taken from http://www-history.mcs.st-and.ac.uk/Mathematicians/Feuerbach.html GeoGebra 互動數學教室 http://www.geogebra.hk

  • Nine-point Circle (Part 1)

  • Nine-point Circle (Part 2)

  • Nine-point Circle (Part 3)

  • Nine-point Circle (Part 4)

  • Feuerbach's Theorem

  • 16 Points of Tangency

Next
Nine-point Circle (Part 1)

New Resources

  • Pythagorean Theorem: Quick Illustrator
  • Untitled
  • רישום חופשי
  • Absolute Value Functions f(x)=a |x - h| + k
  • Function art 3D - waiting shed

Discover Resources

  • Graphing Cosecant Function
  • ShanzaR 20
  • KiteProject
  • Angle trisection and HM
  • Circle Theorems 1 FEQ27

Discover Topics

  • Incircle or Inscribed Circle
  • Differential Equation
  • Centroid or Barycenter
  • Percentages
  • Probability
AboutPartnersHelp Center
Terms of ServicePrivacyLicense
Graphing CalculatorCalculator SuiteMath Resources

Download our apps here:

Download_on_the_App_Store_Badge_US-UK_RGB_blk_4SVG_092917

© 2026 GeoGebra®