NCERT Class 9 Mathematics Ganita Manjari: Chapter 1 — Orienting Yourself: The Use of Coordinates
This chapter, "Orienting Yourself: The Use of Coordinates," from NCERT's Ganita Manjari for Class 9, introduces the fundamental concept of a coordinate system. It explains how numbers can be used to describe the exact physical locations of points and objects, drawing parallels to grid lines on maps. The chapter highlights the ancient Indian origins of coordinate systems, tracing their use from the Sindhu-Sarasvatī Civilisation's urban planning to the geometric constructions of Baudhāyana and the astronomical calculations of Āryabhaṭa and Brahmagupta. It details the evolution of coordinate geometry through contributions from Greek mathematicians like Ptolemy and Arab scholars like Al-Bīrūnī, culminating in René Descartes' formalization of the Cartesian plane. The chapter emphasizes how coordinates bridge geometry and algebra, enabling precise location identification and visualization of equations as shapes. It aims to equip students with the ability to locate objects accurately and understand the relationship between algebraic and geometric representations, preparing them for further study in Grades 9 and 10.
Quick info
| Board | CBSE / NCERT |
|---|---|
| Class | Class 9 |
| Subject | Mathematics |
| Book | Ganita Manjari |
| Chapter | Chapter 1 — Orienting Yourself: The Use of Coordinates |
| Language | English |
| PDF type | NCERT Textbook |
| Session | CBSE 2026 |
| Reading time | 3 minutes |
| Word count | 462 |
Learning outcomes
- Understand the concept of a coordinate system and its use in locating points.
- Appreciate the historical development of coordinate geometry, particularly its Indian contributions.
- Recognize the connection between algebra and geometry through coordinate systems.
- Learn how coordinates are used in real-world applications like mapping and navigation.
Vocabulary
| Word | Meaning |
|---|---|
| Coordinate system | A framework using numbers to describe exact physical locations of points or objects. |
| Grid | A network of horizontal and vertical lines, like on graph paper or a map. |
| Meridian | A line of longitude on a map or globe. |
| Latitude | Angular distance, north or south, from the equator. |
| Longitude | Angular distance, east or west, from the prime meridian. |
| Origin | The point where the coordinate axes intersect, usually denoted as zero. |
| Cartesian plane | A two-dimensional plane defined by two perpendicular axes (x and y). |
| Algebraic equations | Equations involving variables and constants, often representing relationships. |
| Geometric shapes | Figures and forms studied in geometry, such as lines, circles, and polygons. |
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Practice questions
- What is the primary function of a coordinate system? Answer: To use numbers to describe the exact physical locations of points or objects.
- Name an ancient Indian civilization known for using a coordinate system in urban planning. Answer: The Sindhu-Sarasvatī Civilisation.
- Who is credited with formalizing the four-quadrant Cartesian plane? Answer: Brahmagupta (formalized the notion of zero and negative numbers, essential for the Cartesian plane).
- What did René Descartes formalize regarding points in a two-dimensional plane? Answer: That any point could be defined by two numbers representing its distances from two perpendicular axes.
Frequently asked questions
What is a coordinate system?
A coordinate system is a structured framework that uses numbers to describe the exact physical locations of points or objects, similar to grid lines on a map.
Where did the systematic use of grids originate in ancient times?
The first systematic use of grids occurred thousands of years ago in the Sindhu-Sarasvatī Civilisation for urban planning.
What was the significance of Ujjayinī in ancient geography related to coordinates?
Ujjayinī was described as the point marking the central longitude meridian from which all other locations were measured.
How did Brahmagupta contribute to the development of coordinate systems?
Brahmagupta formalized the notion and use of zero and negative numbers, which are essential for modern coordinate systems like the four-quadrant Cartesian plane.
Who is credited with formalizing the Cartesian plane?
René Descartes formalized the concept that any point in a two-dimensional plane could be defined by two numbers representing its distances from two perpendicular axes.
What is the main benefit of using coordinates in mathematics?
Coordinates enable us to locate objects with pinpoint accuracy and visualize algebraic equations as geometric shapes, and vice versa.
Related resources
Important topics
Topics covered
NCERT Class 9 Mathematics — Ganita Manjari — Chapter 1 — Orienting Yourself: The Use of Coordinates. Verified by NCERT Help Editorial Team. Reviewed on 29 Jul 2026. Last updated 10 Aug 2026.