WCircular sectionWConfocal conic sectionsWConic sectionWFocal conicsWAngular eccentricityWBraikenridge–Maclaurin theoremWBrianchon's theoremWCircleWConic constantWDandelin spheresWDirector circleWDroz-Farny line theoremWEccentricity (mathematics)WEllipseWFocus (geometry)WHyperbolaWInellipseWMarden's theoremWN-ellipseWParabolaWPascal's theoremWPoncelet's closure theoremWQvist's theoremWSegre's theoremWSemi-major and semi-minor axesWSteiner conicWSteiner ellipseWSteiner inellipseWTrammel of ArchimedesWUniversal parabolic constantWFile:Drawing an ellipse via two tacks a loop and a pen 2.jpg
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