One of the dictionary definitions of the word eccentric is "not a." Another is "not at the geometric center." Both definitions help in understanding the meaning of eccentricity. A circle and other symmetrical shapes can be formed by "cutting" or passing a through a right circular cone. This creates a cross-sections of the cone. When the cut or plane is perpendicular (at 90 degrees) to the axis of the cone, a circle results. If the plane is positioned at some less than 90 degrees but not quite parallel to the axis, the resulting is an. Within an ellipse can be found two points, called foci. The sum of the distance from each focus to any point on the ellipse is the same for all points. This is also a property of a circle, but in this special type of ellipse, the two foci are superimposed at the same place, which...