NCERT Class 9 Mathematics Textbook for Blind Students made Screen Readable by Professor T K Bansal.

In this chapter, we have studied the following points :

1.
To locate the position of an object or a point in a plane, we require two perpendicular lines. One of them is horizontal, and the other is vertical.

2.
The plane is called the Cartesian, or coordinate plane and the lines are called the coordinate axes.

3.
The horizontal line is called the x -axis, and the vertical line is called the y - axis.

4.
The coordinate axes divide the plane into four parts called quadrants.

5.
The point of intersection of the axes is called the origin.

6.
The distance of a point from the y - axis is called its x-coordinate, or abscissa, and the distance of the point from the x-axis is called its y-coordinate, or ordinate.

7.
If the abscissa of a point is x and the ordinate is y, then (x, y) are called the coordinates of the point.

8.
The coordinates of a point on the x-axis are of the form (x, 0) and that of the point on the y-axis are (0, y).

9.
The coordinates of the origin are (0, 0).

10.
The coordinates of a point are of the form (+ , +) in the first quadrant, (−, +) in the second quadrant, (−, −) in the third quadrant and (+, −) in the fourth quadrant, where + denotes a positive real number and − denotes a negative real number.

11.
If x ≠ y, then (x, y) ≠ (y, x), and (x, y) = (y, x), if x = y.

Acknowledgements

We at blind2visionary, are thankful to
1. Dr. T K Bansal, M.Tech, PhD (IIT Delhi), P.D.F (University of oxford) and former senior lecture from IIT Kharagpur, for planning, organizing and describing this lesson for visually impaired students
2. Mr. Arun kumar for typing and setting this lesson with full devotion and dedication.
3. In case you suggest us any improvement or can point us any mistakes in this lesson your name will also be added to this list of contributors
4. In case you take benefit of our efforts and encourage us by sending your comments, your name will also be added to this list.

End of the Chapter.