This worksheet shows one method of constructing an ellipse or hyperbola. Another method is shown here.
Points A and B are the foci of the ellipse/hyperbola.
Line a passes through the intersections of circles c and d.
The ellipse/hyperbola is the locus of point G, which is the intersection of lines a and b.
Move point D to trace the locus of point G.
Move points A and B to change the shape of the ellipse/hyperbola. Move point A inside the circle centered on point B to change the curve to an ellipse. Move point A outside the circle to change the curve to a hyperbola.
Click here to download the worksheet. Note: you do not need to extract the contents of the Zip file. Simply change the extension from ".zip" to ".ggb" and it will work. You can download an old Geometer's Sketchpad version of this worksheet, here.
Created by Michael Horvath using GeoGebra. Last modified: Monday, 08-Dec-08 13:27:15 PST