Select a linear or non-linear (elliptical or circular) segment.

Select a non-linear segment if you have selected a linear segment
in the first step (at least one of the selection must be a curve).

The two selected segments are now tangent to each other.

Note: For two segments
to be tangent, they must be on the same plane.

Applying a
tangent 2D constraint between elements. Left: between a non-adjacent line and
arc / Center: between adjacent line and arc / Right: between adjacent arcs.