Duke University
Duke University: Web Feats Ii: Altitude Theorem for Equilateral Triangles
This resource provides information about the altitude theorem for equilateral triangles, in addition to links on related topics. Requires Java.
Wolfram Research
Wolfram Math World: Equilateral Triangle
MathWorld goes into detail about equilateral triangles at this site. Use this site to find out how to construct an equilateral triangle using a compass and straight edge. Learn about the altitude of such triangles, and the rationality of...