# The History of Geometry

Geometry's origins go back to approximately 3,000 BC in ancient Egypt. Ancient Egyptians used an early stage of geometry in several ways, including the surveying of land, construction of pyramids, and astronomy. Around 2,900 BC, ancient Egyptians began using their knowledge to construct pyramids with four triangular faces and a square base.

## Euclid's Elements

The next great advancement in geometry came from Euclid in 300 BC when he wrote a text titled 'Elements.' In this text, Euclid presented an ideal axiomatic form (now known as Euclidean geometry) in which propositions could be proven through a small set of statements that are accepted as true. In fact, Euclid was able to derive a great portion of planar geometry from just the first five postulates in 'Elements.' These postulates are listed below:

**(1)** A straight line segment can be drawn joining any two points.

**(2)** A straight line segment can be drawn joining any two points.

**(3)** Given any straight line segment, a circle can be drawn having the segment as
radius and one endpoint as center.

**(4)** All right angles are congruent.

**(5)** If two lines are drawn which intersect a third line in such a way that the sum of
the inner angles on one side is less than two right angles, then the two lines inevitably
must intersect each other on that side if extended infinitely.

Euclid's fifth postulate is also known as the parallel postulate.

## René Descartes' Coordinate Geometry

The next tremendous advancement in the field of geometry occurred in the 17th century when René Descartes discovered coordinate geometry. Coordinates and equations could be used in this type of geometry in order to illustrate proofs. The creation of coordinate geometry opened the doors to the development of calculus and physics.

## The Development of Non-Euclidean Geometry

In the 19th century, Carl Friedrich Gauss, Nikolai Lobachevsky, and János Bolyai formally discovered non-Euclidean geometry. In this kind of geometry, four of Euclid's first five postulates remained consistent, but the idea that parallel lines do not meet did not stay true. This idea is a driving force behind elliptical geometry and hyperbolic geometry.