Geometry Basics

Geometry is the object-oriented part of mathematics and basic geometry is the foundation of geometry.

You will have learned basic geometry concepts.

You will have learned basic geometry definitions.

You will be introduced to basic geometry shapes.

Geometry basics is easy to learn. You will enjoy it.

Basic Geometry Concepts

Geometry is the structure of objects in terms of shape and size.

Are you interested in playing with objects in different shapes and sizes or love to drawing and sketching?

If so, geometry is perfect for you. Let's go to learn geometry basics step by step.

Wait..! Would you mind if this geometry lesson is explained explicitly. Well.

Geometric Dimensions

To study geometric dimension is prerequisite to understand geometry basics. In the same way, to study the following topics those are parts of elementary geometry is prerequisite to understand geometrical dimension.

  • Point
  • Line
  • Plane
  • Solid


A Point is nothing but a position. It has no length or width. So, a point is of no dimension or zero dimension.


A Line is the set of points that extends along a straight path infinitely on and on its opposite direction. It has only length (breadthless length). So, a line is of 1 dimension or simply one d.


A Plane is the two dimensional flat surface that goes on infinitely. It has only length and width. So, a plane is of two dimension.


A Solid has length, width and height or depth. So, a solid is of 3 dimensional geometric shapes.

Therefore, a clear concept of geometrical dimension is must to understand high school geometry.

Geometry discusses the relative position of figures. Basic geometry includes dimension. Zero dimensional or no dimensional geometry is concerned with point. A point is nothing but a position. It has no length, width or heigth. One dimensional geometry is relevant to distance. Because it has only length. Two dimensional geometry is invloved all about area. Because it has only length and width. And 3 dimensional geometry is invloved with volume or space. As volume or space consists of length, width and height.

Origin of Shapes

Point Points make Line Lines make Plane L H W Planes make Solid

Basic Geometry Definitions

Basic geometry includes the fundamental concepts of point, line, plane, angle, curve, surface and space or solid.


A line is the set of points that extends along a straight path infinitely on and on its opposite direction.

Another way ...

A line is a continuous extent of straight length infinitely far on and on its opposite direction without width or depth.

Thus a line includes:

We covered line segment and ray in geometry in another tutorials.

So a line, strictly speaking, is perfectly straight and has no ends in both directions.

It has only length.

So, a line is of one dimension and sometimes called one d.

A line is shown in the figure that extends infinitely in both directions.

Suppose A and B are two distinct points on the line.

It is read AB is a line and denoted by


If you arrange a set of lines one after another, it produces a plane.


A plane is all about two dimensional flat surface that expands infinitely.

The two dimensions are length and width.

The length and width must lie on the same plane.

Thus, a plane has two dimensions.

All 2d shapes lie in the plane.

Three parallel planes are shown in the figure.

Three parallel planes are in 3 different levels.


A figure formed by two rays, inclination to each other, sharing a common endpoint is called an angle. The rays are known as the sides of the angle and the common endpoint is called the vertex of the angle. The measurement of angle is equal to how much two rays or sides are inclined to each other.


A curve is a smoothly-flowing path that may be straight or not. If the curve is straight, it is a line. So, a line is always a curve. Again, if the curve is not straight, it always changes its directions. This type of curve is a one dimensional figure.


A surface is a two-dimensional figure that may be flat or not. A circle, for instance, is a flat surface whereas a sphere is a curved surface. Thus a surface is a generalization of plane; as the plane is a flat surface.


Space is the set of all 3-dimensional points. Space consists of infinite number of points as well as infinite number of planes. In a nutshell, space is the 3-dimensional boundless extent.

Therefore, all objects in space have the relative position and direction.

And objects in space are called solids.

Types of Basic Geometry

Geometry is generally divided into two parts:

Plane Geometry

Plane geometry is all about the geometry of two dimensional geometric shapes.


In mathematics, plane geometry generally refers to Euclidean plane geometry.

This geometry lessons are helpful for those people who are involved in teaching and learning geometry in institution.

Points, line, triangle, quadrilateral, circle, ellipse, parabola, for instance, all are basic geometry shapes under plane geometry that can be drawn on a piece of paper or on a plane.

Plane geometry is also familiar with high school geometry as it is taught in secondary schools all over the world.

Solid Geometry

Solid Geometry deals with shapes and figures of 3 dimensional space.

A solid has 3 edges namely length, width and height.

Thus a solid is of 3 dimensional object.

It mainly discusses the measurements, specially the volume, of solid figures.

High school geometry includes cuboid, cube, cone, cylinder, prism, pyramid, sphere, for example, all are 3 dimensional shapes can be formed in 3 dimensional space.

All of the solid shapes above is part of solid geometry.

The more to study geometry properly, the more to understand solid geometry systematically.

You can learn geometry at wikipedia more.

A cube is showing its faces, edges and vertices.

Solid Geometry Example


A Prism

Yes, we are seeing a prism.

Plane Geometry Shapes


Irregular Quadrilateral (UK)

Trapezium (US)


Trapezium (UK)

Trapezoid (US)

Isosceles Trapezoid

Isosceles Trapezium (UK)

Isosceles Trapezoid (US)

Solid Geometry Shapes

Last revised this page (day/month/year): 03/06/18