Tangent to a Circle
Draws a line tangent from a point to a circle, ellipse, arc, or elliptical arc. There are two possible lines that can be drawn tangent to a circle from a single point. The line drawn is the one closest to the second point.
Point 1: Endpoint for the tangent line
Point 2: Point near the circle
NOTE: The Tangent commands do not work on circles that have been saved in vector form. These entities are not true circles. They are line entities approximating circles. Also, if you are not in 2D Mode, the two lines must lie in the same plane.