RE: back to the well again... parallel trend lines

["Gary Fritz" <fritz@xxxxxxxx>]

> i want to take a known trend line, pick a third point and draw a
> line through it that is parallel to the known trendline.  i
> apologize for the incoherent writing.  my brain is in programmer
> mode i guess. 

OK, try this:

theta = arctangent((X2-X1)/(Y2-Y1)), as before.

Third point is at X3,Y3.

Draw trendline from 
   X3-Z*cosine(theta),Y3-Z*sine(theta) 
to X3+Z*cosine(theta),Y3+Z*sine(theta) ?

I think that's about the simplest way.  If you're picky about where 
the endpoints of the parallel line end up, I'll let you do the trig 
this time.  :-)

Gary