# Introduction to Geometry

Geometry is a subject in mathematics that focuses on the study of shapes, sizes, relative configurations, and spatial properties. Derived from the Greek word meaning "earth measurement," geometry is one of the oldest sciences. It was first formally organized by the Greek mathematician Euclid around 300 BC when he arranged 465 geometric propositions into 13 books, titled 'Elements'. This, however, was not the first time geometry had been utilized. As a matter of fact, there exists evidence to believe that geometry dates all the way back to 3,000 BC in ancient Mesopotamia, Egypt!

Geometry has been the subject of countless developments. As a result, many types of geometry exist, including Euclidean geometry, non-Euclidean geometry, Riemannian geometry, algebraic geometry, and symplectic geometry.

This discussion primarily focuses on the properties of lines, points, and angles. We will also place emphasis on geometric measurements including lengths, areas, and volumes of various shapes. By the end of this section it won't be hard to see that geometry is all around us!

## History of Geometry

Main Lesson: History of Geometry

A brief recap of the development of geometry.

## Applications of Geometry

Main Lesson: Applications of Geometry

How geometry has been used and the impact it continues to make on the world.

## Basic Geometry Terms

Main Lesson: Basic Geometry Terms

The basic concepts of geometry and common terms that will be used throughout your study of geometry.

## Writing Two-Column Proofs

Main Lesson: Writing Two-Column Geometric Proofs

Introduction to two-column geometric proofs as well as step-by-step instructions that aid proof-writing.