Let gamma be a circle with center O and P a point outside gamma.
Construct a tangent line to gamma through point P using a straightedge only.
Prove the construction.
I have a circle centre O on a line PQ.
I lay my straight edge from point P to the edge of the circumference of circle γ and draw the line.
Done!
But! But! But I did choose the tangent point, where the straight edge touched the circumference!
...
Huh? Yeah, sure I did it visual, what do you expect?
See my next comment. I puzzled about this and this did seem to be the only way to go
Edited on March 15, 2008, 7:54 am

Posted by brianjn
on 20080315 07:53:03 