Geometry

History of Geometry

3100 BCE

The earliest known unambiguous examples of written records—dating from Egypt and Mesopotamia about 3100 BCE—demonstrate that ancient peoples had already begun to devise mathematical rules and techniques. Beginning about the 6th century BCE, the Greeks gathered and extended this practical knowledge and from it generalized the abstract subject now known as geometry, from the combination of the Greek words geo (“Earth”) and metron (“measure”) for the measurement of the Earth.

Circles

650 BCE

The first theorems relating to circles are attributed to Thales around 650 BC. Book III of Euclid's Elements deals with properties of circles and problems of inscribing and escribing polygons.

Triangles

624 BCE

Thales of Miletus (624–547 BC) is credited with bringing geometry from Egypt into Greece and laying some early groundwork for the study of triangles. Pythagoras, whose famous theorem is still in use, is hailed as the first 'pure mathematician' to study geometry by applying abstract mathematical concepts.

Plane in Geometry

21

Plane geometry, and much of solid geometry also, was first laid out by the Greeks some 2000 years ago. Euclid in particular made great contributions to the field with his book "Elements" which was the first deep, methodical treatise on the subject

Polygon

700

Polygons have been known since ancient times. The regular polygons were known to the ancient Greeks, with the pentagram, a non-convex regular polygon (star polygon), appearing as early as the 7th century B.C. on a krater by Aristophanes, found at Caere and now in the Capitoline Museum.

Lines in Geometry

1700

Until the 17th century, lines were defined as the "[...] first species of quantity, which has only one dimension, namely length, without any width nor depth, and is nothing else than the flow or run of the point which [...] will leave from its imaginary moving some vestige in length, exempt of any width. [...] The straight line is that which is equally extended between its points."

Angles

1900

Euclid defines a plane angle as the inclination to each other, in a plane, of two lines which meet each other, and do not lie straight with respect to each other. According to Proclus, an angle must be either a quality or a quantity, or a relationship. The first concept was used by Eudemus, who regarded an angle as a deviation from a straight line; the second by Carpus of Antioch, who regarded it as the interval or space between the intersecting lines; Euclid adopted the third concept.