created by Annie Blackadar
Image courtesy of thefamouspeople.com
In his book, Elements, the Greek mathematician Euclid built up the structure of geometry on a fundamental question: what is truth, and how can we be sure about it? To tackle this question, Euclid stripped everything down and decided to start developing geometry at the beginning, defining a set of undefined terms to give geometry a basic vocabulary with which to work.
He then developed a structure of intuitive postulates (sometimes called axioms), or basic ideas that are assumed to be true because they seem so evident. Euclid then began building upon these up step by step, arriving at complex theorems that, assuming the basic axioms are true, can be proved logically to be valid.
This website started as a step-by-step walk through, building up Euclid's structure of geometry from the beginning as taught in Mr. Erlin's Honor's Geometry course at Tamalpais High. However, the website has since branched out, applying the same method of building up from the beginning to teach another subject, also held close to the hearts of ancient Greeks: