# 4: Basic Concepts of Euclidean Geometry

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In Greek, "geo" means earth, and "metron” means measure. Egyptians were among the first people to use geometry to survey the land. The study of geometry was carried on by the Greeks Thales, Pythagoras (550 BC), Plato, and Euclid ( father of geometry, 300 BC). They not only asked “how” and “what” but also asked, “why.” At the foundations of any theory, there are truths, which are taken for granted and can't be proved or disproved. These are called axioms. The first axiomatic system was developed by Euclid in his books called "Elements".

*Thumbnail: This image illustrates in 3D a stereographic projection from the north pole onto a plane below the sphere. Image used with permission (CC BY-SA 4.0; Mark.Howison).*

### Contributor

Pamini Thangarajah (Mount Royal University, Calgary, Alberta, Canada)