The student is told that someone wants to draw an ellipse with a given semi-major axis and eccentricity using a pencil, a string, and two thumbtacks, and is asked to determine what length the string should be for the various values of e and a.
keywords: ellipse, pencil, string, thumbtack, semi-major axis, eccentricity
swf file: ca_renaissance_makinganellipse.swf