Significant Nine Points
The diagram above shows the nine significant points of the nine-point circle. Points D, E, and F are the midpoints of the three sides of the triangle. Points G, H, and I are the feet of the altitudes of the triangle. Points J, K, and L are the midpoints of the line segments between each altitude's vertex intersection (points A, B, and C) and the triangle's orthocenter (point S).
For an acute triangle, six of the points (the midpoints and altitude feet) lie on the triangle itself; for an obtuse triangle two of the altitudes have feet outside the triangle, but these feet still belong to the nine-point circle.
Read more about this topic: Nine-point Circle
Famous quotes containing the words significant and/or points:
“The countenances of children, like those of animals, are masks, not faces, for they have not yet developed a significant profile of their own.”
—W.H. (Wystan Hugh)
“Mankind is not a circle with a single center but an ellipse with two focal points of which facts are one and ideas the other.”
—Victor Hugo (1802–1885)