Note:[br]In the [color=#1e84cc][b]quadric surface[/b][/color] shown below, vertical cross sections are circular. [br][br]What [color=#1e84cc][b]quadric surface[/b][/color]'s definition is dynamically being illustrated in the applet below? [br]How would you write this definition in your own words?[br][br]The [color=#bf9000][b]yellow point [/b][/color]is a point that lies anywhere on this surface. [br]Feel free to drag [color=#bf9000][b]this point[/b][/color] wherever you'd like at any time!
[color=#000000]This applet shows a [/color][color=#bf9000][b]SPHEROID[/b][/color][color=#000000] with circular cross sections that are perpendicular to this solid's major axis. [br][br]Cross sections parallel to any plane containing [/color][color=#bf9000][b]this spheroid's[/b][/color][color=#000000] major axis are ellipses.[br][br]This [/color][color=#bf9000][b]SPHEROID is a locus (set) of points in space, the sum of whose distances from two fixed points (called foci) is constant.[/b][/color][color=#000000] The value of this constant is actually the same as the length as its major axis! [br][br]Compare this illustration with an animated definition of an ellipse, which you can find [url=https://www.geogebra.org/m/hy5zj7Dx]here[/url]. [br][/color]