How do I draw this circle

[marlon]

I need to draw a circle that is tangent to the arc and passing through the upper end point of the blue line, and the center point of the circle should be somewhere along the red line, which is 45 degrees from horizontal. The radius of the circle does not matter.

I should be something like this.

 

Can this be done? thanks!

[eldon]

This I think is a bit more complicated than the last one, and there does not seem to be an exact general solution. I fear that it may involve successive approximation, and that involves quoting a tolerance, so you know when to stop approximating But it can be done approximately.

[stevsmith]

can you add some dimensions please.

[marlon]

I was thinking the same thing. thanks!