Where can I obtain WRITTEN directions for TANGENT lines?

They’re hard to find …

First of all, SketchUp does not have true curves. Arcs and curves in SketchUp are collections of edge segments.

If you wish to have SketchUp’s inferencing snap to a tangent vertex on an arc, set the number of segments to some multiple of 24. (Usually the snap angle is set to 15 degrees, and multiples of 24 should always cause a tangent vertex where two edge segments lie upon the virtual circumference of the arc.)

Sometimes you might need to rotate a circle or arc, so that a tangent vertex or cardinal point is at the place where you wish the tangent edge to be.

Help Search: http://help.sketchup.com/en/search/sketchup/tangent

There may be some plugins that can help:

http://extensions.sketchup.com/en/content/arcs-circles

http://sketchucation.com/pluginstore?pln=TrueTangents

Thank you for the TIME & INFO!

MATH Fctns1 = ø, ellipse