for
Doris Santarone
The Program of Mathematics Education
MacTutor History of Mathematics Site  St. Andrew's University
Math Forum (alias Geometry Forum)
Investigating 
The effects of a, b, & c on 
Quadratics in the xb Plane 
The Nine Point Circle 
A Library of GSP Scripts

Construct a Triangle, Given its Medians

Tangent Circles

Properties of the Orthocenter

Pedal Triangles 
Parametric Equations

Polar Equations 
Fibonnaci Sequence 