| | Circumcircle (Site not responding. Last check: 2007-11-07) |
 | | A circle that passes through each of the vertices of a polygon is called the circumcircle of the polygon.The center of that circle is the circumcenter.Both seem to be truncations of the prefix “circumscribing” attached to the words circle or center.The word circumcircle was suggested in 1883 by W. Hudson in Nature Magazine, according to |
 | | Because the circumcenter must be the same distance from each of the vertices, and because each side of the polygon is a chord of the circle, it is easy to understand that the circumcircle must be at the intersection of the perpendicular bisectors of the sides of the polygon. |
 | | Steiner's theorem, pictured at right, gives a relationship between the radii of five important circles in any triangle, the cirucmcircle, the incircle, and the three excircles (circles tangent to the three sides (or sides extended) of a triangle on the outside of the triangle. |
| www.pballew.net /Circumcircle.htm (396 words) |