Douglas Hofstadter - Feuerbach’s Theorem: A Beautiful Theorem Deserves a Beautiful Proof
UMD Department of Mathematics • 12K views
Math topics:
Triangle geometryRight triangleTriangleCircumscribed circleIsosceles triangleNapoleon's theoremEquilateral triangleCurvesCircleChord (geometry)EllipseGeometryIntersectionGeometryCartesian coordinate systemElementary geometryPerpendicularBisectionEdge (geometry)Inscribed figureAdditionAdditionPlus and minus signsSummation