# [Maths Class Notes] on Non-Euclidean Geometry Pdf for Exam

Geometry is a vital part of mathematics. It discusses the shape and structure of different geometrical figures. Greek mathematician Euclid employed a type of geometry, which studies the plane and solid figure of geometry with the help of theorems and axioms. It is known as Euclidean geometry. Non Euclidean geometry is the opposite of euclidean geometry. Non Euclid geometry is a part of non Euclid mathematics. It discusses the hyperbolic and spherical figures. It is also known as hyperbolic geometry. The figures of non-Euclidean geometry do not satisfy Euclid’s parallel postulate. It is the main reason for the existence of non-Euclidean geometry. In this article, we are going to discuss non-Euclidean geometry in detail.

### Invention of Non Euclidean Geometry

Greek mathematician Euclid presented the concept of Euclidean geometry. At that time, people used to think that there is only one type of geometry called euclidean. A wrong idea was present that all the geometrical figures satisfy Euclid’s parallel postulate. Here comes the concept of non euclidean geometry. The great mathematician Carl Friedrich Gauss realized that all the geometrical figures could not satisfy Euclid’s parallel postulate. The figures that don’t satisfy Euclid’s parallel postulate are non euclidean. Gauss described those figures as non-Euclidean, and thus the concept of non Euclidean space arrived in geometry.

### Spherical and Hyperbolic Geometry

Sphere and hyperbola are two significant figures of geometry. The study of the two-dimensional surfaces of the sphere is spherical geometry. Hyperbolic geometry is to study the behaviour of pseudospherical surfaces and saddle surfaces. Sphere and hyperbola are the main two figures of non Euclidean geometry. Hence, it is also known as hyperbolic geometry. Sphere, hyperbola, and other non Euclidean figures do not satisfy Euclid’s parallel postulate. These are the figures of non Euclid geometry, which are different from the Euclidean figures for the theorems and axioms.

### Types of Non Euclidean Geometry

In geometry, two types of figures are there based on Euclid’s parallel postulate. The figures that do not satisfy the parallel postulate are non euclidean. These figures are mainly of two types – hyperbola and ellipse. Non Euclidean geometry is classified based on the shape of the figures, elliptical geometry, and hyperbolic geometry. These two branches discuss the characteristics of the respective figures.

### Hyperbolic Geometry for Dummies

Hyperbolic geometry is a branch of non Euclidean geometry. It is not valid for the fifth parallel postulate of Euclid. The fifth postulate states that one given line is parallel with only one other line through a point, not a line. There are at least two lines in hyperbolic geometry that are parallel with a given line through a point, not a line. The properties of a triangle are different from the Euclidean geometry. The sum of angles in Euclidean geometry is 180. The sum of angles of a triangle is less than 180 degrees in this branch. The area and surface formulas of hyperbolic geometry are different from the Euclidean geometry.

### Elliptical Geometry

Another type of non Euclid geometry is elliptical geometry. It is the study of the figures created on the surface of an ellipse. It doesn’t satisfy Euclid’s parallel postulate. It studies three-dimensional figures, unlike Euclidean geometry. Elliptical geometry has a considerable application in cosmology, astronomy, and navigation. It is used in linear algebra, arithmetic geometry, and complex analysis. For accurate calculation of area, angle, distance on the earth, elliptical geometry is used. The triangles in elliptical geometry act like a non euclidean geometry triangle. The sum of these angles of these triangles is 180°.

### Applications of Non Euclidean Geometry

Non Euclidean geometry has a considerable application in the scientific world. The concept of non Euclid geometry is used in cosmology to study the structure, origin, and constitution, and evolution of the universe. Non Euclid geometry is used to state the theory of relativity, where the space is curved. The measurement of the distances, areas, angles of different parts of the earth is done with the help of non Euclidean geometry. Also, non Euclid geometry is applied in celestial mechanics.

### Did You Know?

The way to build space in non Euclidean geometry is called non Euclidean architecture. As soon Euclidean figures do not satisfy Euclid’s parallel postulate, they create some unique figures. These figures bring variety to the architecture. The architecture includes all the various figures that are different from the regular Euclidean figures. Non Euclidean architecture is used in creating models, designing different shapes and figures. It makes some new and elegant models and sculptures.