Nine-Point Conic
NinePointConic
A conic section on which the midpoints of the sides of any complete quadrangle lie. The three diagonal points P, Q, and R also lie on this conic.
See also
Complete Quadrangle, Conic Section, Diagonal Points, Nine-Point CircleExplore with Wolfram|Alpha
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Cite this as:
Weisstein, Eric W. "Nine-Point Conic." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Nine-PointConic.html