TAN PT allows you to create a line tangent to a selected
entity, and through a specified reference point.

Select the desired entity, near the point of tangency.

Indicate the reference point through which the tangent 
line will pass, using a Position Menu option.

An error message is displayed if you are constructing in 
3-D and the entities you select are not coplanar, or if 
the reference point is on the selected entity and the 
L-LIMIT switch is set to FUNCTN. The error message 
indicates that these settings and selections result in 
a zero-length line. If this occurs, change the line 
limits and press <Enter>, or reselect the desired entity 
and reference point.

With the L-LIMIT switch set to FUNCTN, the tangent line is 
created with the reference point and the tangency point as
its endpoints.

If the reference point is on the selected entity and the 
L-LIMIT switch is set to VIEWPORT, the line is tangent to 
the selected entity at the specified reference point, and 
the line extends to the screen limits.
