The graphic is bad, for it looks like it was a really early edition of Sketchpad, things do not line up quite right and I do not like the way I wrote it up, the write up gets the right answer, but it is sloppy. So, that is todays project. The line up problem is due to the wmf export program it was using, in the program it was always perfect, the wmf export eventually became perfected, but now it uses emf export.
Two circles that take up a line, tangent to each other, place a third circle tangent to those two and tangent to the circle which circumscribes the line. It is part of demonstrating how to use a power line, but as I said, it is chunky, and I going to whip up a better batch. The power line is essential to placing circles tangent to each other. I developed a number of equations for it in the Delian Quest,
I downloaded a bunch of Pete Seeger, Melanie, and the Seekers, which make me wish I could take some time to play along on my harmonicas. but, no time.