Chapter 1 of Class 9 Maths Ganita Manjari Part 1 is Orienting Yourself: The Use of Coordinates. It introduces the Cartesian coordinate system — a way to describe the exact position of a point on a flat surface using two numbers. These Class 9 Mathematics Chapter 1 solutions are also useful as quick revision notes before exams.
The Cartesian Plane
A Cartesian plane is formed by two perpendicular number lines: the horizontal x-axis and the vertical y-axis, intersecting at the origin (0, 0). Together they divide the plane into four regions called quadrants (I, II, III, IV, numbered anticlockwise starting from the top-right).
Coordinates of a Point
Every point in the plane is described by an ordered pair (x, y): the abscissa (x-coordinate) is the distance from the y-axis, and the ordinate (y-coordinate) is the distance from the x-axis. The order matters — (2, 3) is a different point from (3, 2).
Sign Conventions in Each Quadrant
- Quadrant I: (+, +)
- Quadrant II: (−, +)
- Quadrant III: (−, −)
- Quadrant IV: (+, −)
A point on the x-axis has y-coordinate 0; a point on the y-axis has x-coordinate 0.
Plotting Points
To plot a point (a, b): move a units along the x-axis (right if positive, left if negative) from the origin, then move b units parallel to the y-axis (up if positive, down if negative).
Class 9 Mathematics Chapter 1 – Notes and Extra Questions
Along with these NCERT Solutions, students can also use the Class 9 Mathematics Chapter 1 Extra Questions and Class 9 Mathematics Chapter 1 Revision Notes for quick revision and extra practice.
