Question 337598
Here's a couple of links.
That's a pretty complication construction and better handled this way.
If you don't like those, then just search on nine-point circle.
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http://mathworld.wolfram.com/Nine-PointCircle.html
http://jwilson.coe.uga.edu/EMT668/EMT668.Folders.F97/Anderson/geometry/geometry1project/construction/construction.html