At 12:07 10/12/1999 -0600, Alfredo wrote:
>
>I have the feeling that this is a special case (all radii = 1) of
>general Soddy Circles (whose radii can be different).
>
>See http://www.treasure-troves.com/math/SoddyCircles.html for an
>excellent description and an excellent graphical treatment:
>
>        Given three distinct points A, B, and C, let three Circles
>        be drawn, one centered about each point and each one tangent
>        to the other two...
>
>

Oddly enough, when I was at Ford Motor in computer graphics, supporting
Ford's home-grown graphics system (since replaced by SDRC), I had to write
a program to find the inner Soddy circle given three arbitrary arcs. The
purpose of this was to make sure that a shaft or other part that was
circular in its cross-section actually cleared the things it was supposed
to without forcing the designer to look at several different views.

So, if anyone in the class Jeff's wife was observing asks if there are
real-world applications for the stuff they are studying, the answer is yes!


Tom Brandt                            Northtech Systems, Inc.
+1 734-769-5040                     313 N. First Street
+1 734-769-5498 (FAX)            Ann Arbor, MI 48103