In this chapter, we will learn the basic concepts of plane geometry. For a better understanding, let us first define the general concept of geometry:
Geometry is a scientific discipline of mathematics that deals with the spatial characteristics of bodies and their interrelationships.
The most familiar space to us is the three-dimensional (with the abbreviation 3D) space, which is also our living environment. It is determined by three dimensions, length, width and height.
In the three-dimensional space, there are geometric bodies that also extend in three dimensions. This includes practically all objects we know from everyday life. The properties of geometric bodies are studied by the mathematical branch of Stereometry and will be discussed in a special chapter, Geometry in Space.
Plane geometry, however, focuses on only two dimensions, length and width:
Geometry in the plane or planimetry is a mathematical branch that studies the properties of geometric figures in a plane.
Plane is a flat surface in three-dimensional space. It has only two dimensions, length and width.
A geometric figure is a condensed set of points located in a plane and bounded by a closed curve or a broken line.
Before discussing geometric figures, let us first look at the basic concepts of plane geometry, which include:
Distance and
A special chapter is also devoted to parallelism and orthogonality, which are considered to be the fundamental relations between geometric elements, both in the plane and in space.
