In any triangle, one can locate a circle which passes through the midpoints of that triangle's edges, the midpoints of its perpendicular segments, and the feet of a given triangle's perpendiculars. In this sketch, drag the vertices of the yellow triangle to alter the triangle.
The Nine Point Circle, and sketches like it, will be vastly more useful in DR2, which will support labels for objects. (With DR1, the absence of labels makes it difficult to distinguish which of the nine points is which---though a more elaborate sketch could identify them by coloration, size, or other physical properties.)
Go back to the JavaSketchpad demo gallery.
This page was created in part by the DR1 release of JavaSketchpad, a prototype component of The Geometer's Sketchpad. Copyright ©1990-1997 by Key Curriculum Press, Inc. All rights reserved. Portions of this work are being funded by the National Science Foundation (award DMI-9561674 ).