I have a unique situation where I need to calculate programmatically the point as indicated in the picture below. The known dimensions, points, and angles are shown as "known" or a value. The shape is subject to change at any time with the exception of the relationship of the shortest known length line to the top line. The indicated angle will always be 90 degrees.
I need to be able to calculate the final point, in lisp, without resorting to drawing temporary objects, since the operation may take place on drawings that are not open in the editing window.
I can do it really easily by drawing a circle and then a line tangent to the circle, but that requires manually editing the drawings.
Since I am having a difficult time with calculus this morning, I thought some kind soul would help me with the mathematics so I can tranfer it to lisp.