Wolfram Research
Wolfram Math World: Distance
MathWorld.com gives a formula for finding distance using the Pythagorean theorem. The formula for finding the distance between two points in Euclidean space is given on this page. The page has links to related topics.
Other
Mathpages.com: History of Mathematics
Find the information you need about math history, from Archimedes to Fermat. A great resource for studying the foundations of today's world of mathematics.
National Council of Teachers of Mathematics
The Math Forum: Famous Problems in the History of Mathematics
On this site, there are several math problems to explore and solve. Look through some solutions by famous mathematicians and expand your thinking about some interesting math concepts. Teachers of elementary grades may want to use this...