## What is Geometry?

Geometry is a branch of mathematics involving measurement, properties, and relationships of figures and spaces. The term geometry comes from the Greek words *geo* and *metry* for *Earth* and *measurement*, respectively. Geometry has various real-world applications, from construction and architecture to biology, arts, and animation. As one of the oldest branches of mathematics, geometry concepts were developed to solve problems involving land wealth, surveying, and astronomy. The study of geometry includes topology, trigonometry, algebraic geometry, and differential geometry. Like much of mathematics, geometry is interconnected with other branches of math. Geometry and algebra are both essential for concepts such as parallel lines and angle measurements. Geometry and probability are central in measuring sample spaces.

Geometry is a core element in comprehensive mathematics education. Students in preschool begin exploring skills and concepts in geometry. Beginner geometry concepts include a study of lines, angles, and polygons. Students learn how to calculate the area, perimeter, and volume of figures. Students also explore pi and circles. Secondary-level geometry courses explore the Pythagorean Theorem and its applications to right angles and distances. Typical high school geometry courses also introduce inductive and deductive reasoning and geometric proofs. An introductory college course in geometry consists of an overview of the measurement of two-dimensional and three-dimensional figures, theorems, axioms, and postulates.

Geometry skills and concepts are embedded in every grade level in most math curricula in the United States, with a specific course in high school. Technical vocabulary is essential in geometry, so including geometry definitions is vital in any instructional resource.