Path: utzoo!utgpu!watmath!att!tut.cis.ohio-state.edu!cs.utexas.edu!csd4.milw.wisc.edu!mrsvr.UUCP!hallett
From: hallett@mrsvr.UUCP (Jeff Hallett)
Newsgroups: comp.graphics
Subject: Tangents to Three Circles
Message-ID: <859@mrsvr.UUCP>
Date: 8 Aug 89 18:49:12 GMT
Reply-To: hallett@gemed.ge.com (Jeff Hallett)
Organization: GE Medical, MR Center, Milwaukee
Lines: 19
Organization:GE Medical Systems, Waukesha WI


I have an interesting geometry problem.  Given three circles, I need
to be able to find a circle tangent to all three.  I realize that,
as specified, there are upto 6 possible solutions, but there is
always one.  I place no constraints such as circumscription or
disjoint unions, but would like the solution to find all possible
tangential circles to the given three and provide some mechanism to 
choose one from the set.

Any help would be appreciated.  I've worked on this a long time and
it is not really a simple geometry problem.

Thanks much.

-- 
                Jeffrey A. Hallett, PET Software Engineering
                    GE Medical Systems, W641, PO Box 414
                            Milwaukee, WI  53201
           (414) 548-5173 : EMAIL -  hallett@postron.gemed.ge.com