A deceptively simple question setup leads to a number of attack methods and a surprisingly sophisticated solution set in this open-ended problem. Young geometers of different strengths can go about defining the solutions graphically,...

Ellipse as a locus of points using Cabri Jr.

Students investigate the definition of a parabola through one of its geometric definitions. They study conic sections. They examine an ellipse as a locus of points such that the sum of distances from the foci to the traced path is constant.

This site defines a locus and introduces five theorems about loci. Click on the "Topic Index" link to find related practice activities and resources.

This site defines what a locus is and offers links to five locus theorems. Walks you through the six "Steps to solving a locus problem."

Use this site to investigate the third theorem of loci, equidistant from two points. Click on the "Topic Index" link to find related practice activities and resources.

Loci are applied to word problems in this online tutorial. Practice problems are included. The teacher resource page supplies practical problems.