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Re: Fast help for circle problem


Funny thing -- a fellow engineer asked me this same type of question a
few months ago.  This is a classic four-bar linkage problem.  Look up
the answer in a dynamics textbook.  The four bars are joined at the
centers of the circles.

Regards,

Mark E.


jmittag wrote:
> 
> We are looking for a solution for the following problem:
> 
> Given are 3 circles, each with center coordinates and radius. Circle 1
> is touching circle 2 and circle 2 is touching circle 3 (without any
> intersection). As a special case circle 1 is also touching circle 3.
> 
> We are looking for circle 4, which is touching circles 1 to 3.
> 
> The equation for one circle "i" is as follows:
> 
> (ri+r4)^2=(x4-xi)^2+(y4-yi)^2   with i = 1,2,3
> 
> We need a symbolic solution for x4, y4 and r4.
> 
> Thanks in advance!
> 
> Jens Mittag
> 
> email: Jens.Mittag at tu-berlin.de



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