I'm trying to draw a circle in VB that will be tangent to a line... don't know how to specify where to start.

 

A circle must be tangent to a "point" on a line . . .

The center of the circle has to lie on the radius/diameter that is perpendicular to the slope of the line at the lines tangent point.

Determine slope, m, of line at the point of intersection.
Calculate perpendicular slope: -1/m
Find the coordinates for the center along the slope.
Calculate the circle.