A Chain of Touching Circles in a Polygon
(à la Bui Quang Tuan)


This applet requires Sun's Java VM 2 which your browser may perceive as a popup. Which it is not. If you want to see the applet work, visit Sun's website at http://www.java.com/en/download/index.jsp, download and install Java VM and enjoy the applet.


Buy this applet
What if applet does not run?

The applet illustrates an extension of a 6 circles theorem due to Bui Quang Tuan from triangles to convex polygons with more than 3 sides.

Given a convex n-gon A1A2...An (n ≥ 3 and odd), start with inscribing a circle C1 into ∠A3A1A2 and note point T12 of tangency on the side A1A2. Next inscribe circle C2 into ∠A1A2A3 so that it is tangent to A1A2 at T12 and note point T23 of tangency with side A2A3. Continue inscribing circles C3, C4, C5, and so on, into successive angles. Then C2n = C1.

For regular polygons, the length of the chain may be 1 or 2N.

The situation appears to be analogous to an extension of another 6 circles theorem.

(The applet can emphasize successive pairs of circles counting from 0 to 2n - 1. When that attribute equals 2n, all the circles are displayed in the same color.)

|Activities| |Contact| |Front page| |Contents| |Geometry| |Store|

Copyright © 1996-2012 Alexander Bogomolny

 41143704

A math books store at a unique math study site. Shopping at the store helps maintain the site. Thank you.
Sites for teachers
Sites for parents
Terms of use
Awards
Interactive Activities

CTK Exchange
CTK Wiki Math
CTK Insights - a blog
Math Help
Games & Puzzles
What Is What
Arithmetic
Algebra
Geometry
Probability
Outline Mathematics
Make an Identity
Book Reviews
Stories for Young
Eye Opener
Analog Gadgets
Inventor's Paradox
Did you know?...
Proofs
Math as Language
Things Impossible
Visual Illusions
My Logo
Math Poll
Cut The Knot!
MSET99 Talk
Old and nice bookstore
Other Math sites
Front Page
Movie shortcuts
Personal info
Privacy Policy

Guest book
News sites

Recommend this site

Sites for parents

Education & Parenting

Search:
Keywords:

Google
Web CTK
Supported by
3wVentures