Wolfram Research
Wolfram Math World: Math World: Geometric Construction
Offers an explanation of what a geometric construction is and what some of the tools are that are used for it, including the traditional straightedge and compass. The site explains how to construct various polygons inscribed within a...
Other
Advogato: Trigonometry by Geometric Construction
This site from Advogato is all about angles. It contains information starting with what an angle is and what it looks like, all the way up to bisecting angles and theorems about angles. This is very good information for students just...