---
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id: "66f15980e361cd99fe370e8b"
title: "Introduction to Three Dimensional Geometry"
board: "CBSE"
curriculum: "CBSE"
class: "Class 11"
subject: "Mathematics"
book: "Mathematics"
chapter: "Introduction to Three Dimensional Geometry"
chapter_slug: "introduction-to-three-dimensional-geometry"
canonical_url: "https://www.edzy.ai/cbse-class-11-mathematics-introduction-to-three-dimensional-geometry"
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version: 1
last_updated: "2026-06-20"
---

# Introduction to Three Dimensional Geometry

In this chapter, we study the basic concepts of geometry in three-dimensional space, which involves understanding the coordinates that define the position of a point in a space using three numbers representing distances from mutually perpendicular planes.

---

## Knowledge Snapshot

| Field | Details |
| :--- | :--- |
| Class | Class 11 |
| Subject | Mathematics |
| Book | Mathematics |
| Chapter | Introduction to Three Dimensional Geometry |
| Pages | 108-216 |

---

## Chapter Summary

### Short Summary
This chapter introduces the concept of three-dimensional geometry, focusing on the coordinates required to locate points in three-dimensional space.

### Detailed Summary
Three-dimensional geometry involves using three coordinates to specify the position of a point in space, represented as (x, y, z). The coordinate system consists of three mutually perpendicular planes intersecting at an origin, delineating the space into octants. The chapter explains the relationship between points in space and their corresponding coordinates by describing how to derive coordinates based on vertical and horizontal distances to the axes. The chapter concludes with the implication of the signs of coordinates determining the octant in which a point lies.

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## Topic-Wise Explanation

### Introduction
The introduction emphasizes the necessity of three coordinates to describe a point in space, as opposed to just two in a plane.

### Coordinate Axes and Coordinate Planes in Three Dimensional Space
This section defines the x, y, and z-axes and their importance in forming the rectangular coordinate system and the associated planes—XY-plane, YZ-plane, and ZX-plane.

### Coordinates of a Point in Space
Coordinates (x, y, z) are explained through practical scenarios, illustrating how to find a point's position by dropping perpendiculars to established planes.

### Distance between Two Points
This topic is absent; no specific details are provided in the context.

---

## Core Ideas

| Idea | Explanation |
| :--- | :--- |
| Coordinates | Ordered triplets (x, y, z) represent a point in three-dimensional space. |
| Origin | The point where the three axes intersect is the origin, denoted as (0, 0, 0). |

---

## Key Concepts

| Concept | Meaning |
| :--- | :--- |
| Octants | The eight divisions of space created by the three coordinate planes. |

---

## Important Points for Revision

* A point in space requires three coordinates (x, y, z).
* The coordinate system includes three mutually perpendicular axes and planes.
* The origin is represented as (0, 0, 0).
* Octants are determined by the signs of the coordinates.
* Spatial coordinates can change depending on the octant.
* Each coordinate corresponds to the perpendicular distance from a specific plane.
* A point's location in space can be derived from its coordinates through perpendicular projections.

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## Practice Questions

### Short Answer Questions
1. Define the coordinates of a point in three-dimensional space.
2. What are the three coordinate planes?
3. Explain what an octant is.
4. How does the coordinate system divide space?
5. Describe the importance of the origin in three-dimensional geometry.

### Long Answer Questions
1. Discuss how to find the coordinates of a point given its position in space.
2. Explain how the signs of coordinates determine in which octant the point lies.
3. Provide detailed steps to derive the coordinates of a point P in space based on its perpendicular distances from the coordinate planes.

---

## Source Attribution

| Field | Value |
| :--- | :--- |
| Source | Edzy |
| Reference Type | examSubjectBookChapter |
| Reference ID | 66f15980e361cd99fe370e8b |
| Canonical URL | https://www.edzy.ai/cbse-class-11-mathematics-introduction-to-three-dimensional-geometry |
| Markdown URL | https://www.edzy.ai/okf/chapter/cbse-class-11-mathematics-introduction-to-three-dimensional-geometry.md |