# Point – Definition With Examples

Created on Dec 19, 2023

Updated on January 6, 2024

Welcome to another exciting exploration with Brighterly, where we bring the abstract concepts of mathematics alive, right before your eyes! Today, we delve into the very foundation of all geometrical and algebraic concepts — the humble but mighty point. Imagine standing in a vast, infinite universe, where your position is unique, unduplicated. This is the abstract world of mathematics, and you are a point in this world, occupying a unique space. But what does it mean to be a point? In this article, we unravel this concept, illuminate its properties, and embark on a journey from one-dimensional to multi-dimensional spaces. As always, we’ll journey from definition to application, real-world examples to pure mathematics, ensuring you have a 360-degree understanding. So put on your explorer’s hat, join us at Brighterly, and let’s journey into the fascinating world of points!

## What is a Point?

In the colorful world of mathematics, terms often carry a special meaning, distinct from their everyday use. One such term, fundamental to the field, is a point. A point represents a precise location or place in space, a specific spot within the vast mathematical universe. It’s like the smallest dot you could possibly make with your pencil, but in the abstract world of mathematics, it has no size, no length, no width, no depth. It’s a location, nothing more. The intriguing paradox of a point’s nature—being both something and nothing—is a captivating concept for young learners on their mathematical journey.

## Definition of a Point

According to the traditional Euclidean Geometry, a point is defined as ‘that which has no part’. Simply put, a point is an entity that has position but no size or shape. In the abstract language of mathematics, it is just a set of coordinates that indicates a specific location in a given space, which could be one-dimensional, two-dimensional, or extend to multiple dimensions.

## Examples of Points

Understanding what a point means can be initially challenging, as it’s such an abstract concept. But worry not! Let’s look at a few examples.

## Real-World Examples of Points

Think of a city on a map, or a star in the night sky, or even the tip of a needle. Each of these could be considered a point. In each instance, we focus on the location, not the size or shape of the object.

## Mathematical Examples of Points

In a mathematical context, a point could be represented by a dot on a number line or a graph. For instance, the point (0,0) on a two-dimensional graph, commonly known as the origin, or the point (3) on a number line.

## Properties of Points

### Definition of the Properties of a Point

A point, as we have established, is a unique location in space with no size or dimensions. However, when multiple points are connected, they can define length (as in a line segment), shape (as in a polygon), or even volume (as in a polyhedron).

### Common Properties of Points

Points are fundamental in defining mathematical structures. Two points define a line, three non-collinear points define a plane, and so on. A point’s position is uniquely determined by its coordinates.

## Point in Various Dimensions

### Points in One-Dimension

A point in one-dimension is typically represented on a number line. The position of the point is determined by its single coordinate, often denoted by an integer or a real number.

### Points in Two-Dimensions

On a two-dimensional plane, a point is described by an ordered pair of numbers (x,y), known as Cartesian coordinates. These represent the distance of the point from the two perpendicular axes.

### Points in Three-Dimensions

In three-dimensional space, a point is denoted by three coordinates (x,y,z). These represent the point’s distance from three planes intersecting at the origin.

### Points in Higher Dimensions

For spaces with more than three dimensions, a point is denoted by an n-tuple of real numbers, where ‘n’ represents the number of dimensions.

## The Importance of Points

### The Role of Points in Geometry

In geometry, points serve as the foundation for more complex structures. Lines, angles, shapes, and solids all begin with points. Even curves and surfaces are collections of infinitely many points!

### The Role of Points in Algebra

In algebra, points are used to represent solutions to equations on a graph. The coordinates of a point can be solutions to one (on a number line), two (on a 2D plane), or more equations.

## Equations Involving Points

### Definition of Equations Involving Points

In mathematics, equations involving points usually refer to geometric relations or algebraic equations where the solutions represent points in a certain space.

### Solving Equations Involving Points

Solving these equations usually involves determining the coordinates that satisfy the given conditions. This often requires knowledge of algebraic rules and geometric principles.

### Writing Equations Involving Points

When writing equations involving points, we typically write the coordinates of the points as variables in the equation, which represents a mathematical relationship that the points adhere to.

### Tips for Writing Equations Involving Points

When writing equations involving points, it’s crucial to understand the relationship between the points. Do they form a line? A circle? Or do they satisfy a more complex relationship? Knowing the equation’s form is often a good first step.

### Practice Problems for Writing Equations Involving Points

Try these practice problems to sharpen your skills:

- Write the equation of a line that passes through the points (2,3) and (4,5).
- Write the equation of a circle with the center at (0,0) and passing through the point (3,4).

## The Point Line Plane Postulate

### Definition of the Point Line Plane Postulate

The Point Line Plane Postulate is a fundamental concept in geometry. It stipulates that:

- Two points determine a line.
- Three non-collinear points determine a plane.
- A line and a point not on the line determine a plane.

### Implications of the Point Line Plane Postulate

These postulates help us define the fundamental geometric structures and develop a consistent framework for geometric reasoning.

### Practice Problems on Points

Here are a few problems to hone your understanding of points:

- Identify the coordinates of the point halfway between (4,6) and (8,10).
- Find the distance between the points (3,4) and (5,9).

### Problems Involving Points in Two-Dimensions

Try these two-dimensional challenges:

- If point A(2,3) and point B(5,6) define a line, what’s the slope of that line?
- What is the area of the triangle formed by points A(2,3), B(4,5), and C(6,7)?

### Problems Involving Points in Three-Dimensions

And some three-dimensional ones:

- What are the coordinates of the point that is equidistant from (1,2,3), (4,5,6), and (7,8,9)?
- If points A(1,2,3), B(4,5,6), and C(7,8,9) define a plane, what is the equation of that plane?

### Problems Involving Points in Higher Dimensions

For the advanced learners, try to visualize these:

- What is the distance between the points (1,2,3,4) and (5,6,7,8) in four-dimensional space?
- What is the hyperplane defined by the points (1,2,3,4), (5,6,7,8), and (9,10,11,12) in four-dimensional space?

## Conclusion

And there you have it! We’ve journeyed through space and dimension, understanding the fundamental concept of a point. As we’ve seen, a point, simple as it may seem, carries profound significance in both geometry and algebra. As with everything else in mathematics, understanding the basics well opens doors to more complex concepts. Here at Brighterly, we believe in making these basic concepts interesting, relatable, and understandable, sparking your imagination and fostering an enduring love for learning. We hope you enjoyed this journey as much as we did! Keep exploring, keep questioning, and let’s make learning brighter and more joyful together!

## Frequently Asked Questions on Points

### What is a point?

A point in the field of mathematics is an entity that indicates a specific position in a particular space. Despite its undefined size or volume, a point represents an exact location in any dimension, whether it’s on a simple one-dimensional number line, a two-dimensional plane, a three-dimensional space, or beyond into the realm of multi-dimensional spaces.

### How do you define a point?

The definition of a point comes from ancient Greek philosopher Euclid’s ‘Elements’, where he described a point as ‘that which has no part’. In more modern terms, we understand a point as a set of coordinates, the fundamental unit of space. Regardless of the number of dimensions, a point always represents a unique location in that space.

### What are some properties of points?

Points, though simple, have some key properties. Firstly, a point represents a unique position in space and is usually described through its coordinates. Secondly, points serve as building blocks for more complex structures in geometry; they’re the seeds from which grow our lines, shapes, volumes, and multi-dimensional structures. Lastly, the relationship between points often defines geometric and algebraic rules and principles. For instance, two points define a line, while three non-collinear points define a plane.