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Tangible Math

Case Studies - Photo Gallery

Dandelin Spheres Ellipse Sculpture

The four poles suggest the outline of the cone. The two spheres are tangent to the cone and to the diagonal plane that intersects the cone. The intersection of the diagonal plane and the cone is the ellipse; the points of tangency between the spheres and the diagonal plane form the foci of the ellipse. Version 2 Professor Nemirovsky uses the sculpture to illustrate a property of the ellipse. Segments of equal length Using yarn to illustrate additional properties of the ellipse A student gets an up-close look at the piece Taking advantage of the scale of the piece, students investigate properties of the ellipse.