Does anyone know how to draw a curve of a specified radius connecting two previously drawn line ends? In this instance I don't know the location of the center point. The attached drawing shows the issue. The smaller sketch shows the four possible ways that a curve of a given radius could be drawn through a pair of points.
For that matter, suppose I wanted any entity, such as an ellipse, to pass through these line ends. Is there a way to pre-draw the shape, then move it and snap it to the line endpoints?