Line (tan,tan)

 From:  Frenchy Pilou (PILOU)
5253.9 In reply to 5253.8 
Yes its the same even more easy!

Call Line
Now just helper lines
AB each center of circle
AN Radius perpendicular to AB (NN' if you want the 2 tangents extern)
BM Radius perpendicular to AB (MM' if you want the 2 tangents extern)
NM
AJ = intersection with NM
JA Reorient it (Rotate from J toward N Tan..gent : first click
Tangent on second circle : second click
et voilĂ  :)
Here the image :) sorry for bad visibility it's my fault not Moi :)

EDITED: 13 Jul 2012 by PILOU