Euclidean geometry edit
Euclid set forth the first known axiomatic treatment of geometry.[citation needed] He selected a small core of undefined terms (called common notions) and postulates (or axioms) which he then used to prove various geometrical statements. Although the plane in its modern sense is not directly given a definition anywhere in the Elements, it may be thought of as part of the common notions.[1] In his work Euclid never makes use of numbers to measure length, angle, or area. In this way the Euclidean plane is not quite the same as the Cartesian plane.
- ^ Joyce, D. E. (1996), Euclid's Elements, Book I, Definition 7, Clark University, retrieved 8 August 2009