Draw a circle tan to a line and intersects a point. Radius unkown.

[guitarguy1685]

This is really more of a geometry exercise. How can I draw a circle that is tangent to a line and crosses a given point. The radius is unknown. See image below.

 

Currently I just draw a circle and move the bottom quadrant to the line. Then I scale the circle (eyeballing it) until it looks like it crosses that point I set. Thanks in advance for your help.

[guran]

Command Arc, start point at the tangent point, "e" for end point at the the intersect point and then "d" for direction.

[rkent]

edit: misread question

 

Mirror the vertical line about the tangent point of the horizontal, use 3p circle, pick endpoints on vertical and tangent point.

Edited August 1, 2016 by rkent

[paulmcz]

Circle center will lie on intersection of an xline, perpendicular to the line at the point of tangency and an xline, running through a midpoint and perpendicular to a line connecting point of tangency and point of intersection with the circle.

[paulmcz]

This is how I'd do it.

[guitarguy1685]

oh wow so many option! Why did I make this so hard on myself? Thanks guys. I tried them all!

[rkent]

oh wow so many option! Why did I make this so hard on myself? Thanks guys. I tried them all!

 

Are you saying that the circle passes thru two known points and is tangent to the horizontal line? If so there is only one radius that will work. If the circle is tangent to the horizontal line anywhere along that line then there are multiple radius' that will work

[guitarguy1685]

Yes, that's what I meant to say. And your right, only 1 radius will work. I think Eldon's option doesn't get me quite there. The others seem to work.

[eldon]

It appears that I also mis-understood the problem, so I have deleted my previous post.

 

The correct solution was given in the first reply by guran.

 

If you wanted the whole circle, then use the center of the arc

Edited August 2, 2016 by eldon
added provision for circle