Coordinate Geometry Class 9 Notes - Chapter 3

CBSE Class 9 Maths Coordinate Geometry Notes:-Download PDF Here

Coordinate geometry is significant because it provides a link between geometry and algebra through line graphs and curves. Coordinate geometry is useful in mathematics because it allows us to locate points on any plane. It also has applications in trigonometry, calculus, and other disciplines. Coordinate Geometry for class 9 notes is given here. Get the complete concept of coordinate geometry such as cartesian system, coordinate points, how to plot the points in the coordinate axes, quadrants with signs, and so on. Go through the below article to learn coordinate geometry for class 9.

Coordinate Geometry

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Cartesian System

The cartesian system is a system for describing the position of a point in a plane. A point is located by referring two perpendicular lines in a cartesian system. The X-axis is the horizontal line XX’, and the Y-axis is the vertical line YY’.

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Origin

The origin, indicated by the letter ‘O,’ is the place where the horizontal and vertical lines intersect. Here, positive directions are OX and OY, while negative directions are OX’ and OY’.

Origin

Coordinate Axes and Quadrants

The plane is divided into four sections by the X and Y axes. The quadrants (one-fourth section) are numbered I, II, III, and IV in anti-clockwise order from OX. The cartesian plane, also known as the coordinate plane or the XY plane, comprises these axes and quadrants. These axes are also known as coordinate axes.

Coordinate Geometry class 9-1

Points in Different Quadrants.

Signs of coordinates of points in different quadrants:

I Quadrant: ‘+’ x – coordinate and ‘+’ y – coordinate. E.g. (2, 3)

II Quadrant: ‘-’ x – coordinate and ‘+’ y – coordinate. E.g. (-1, 4)

III Quadrant: ‘-’ x – coordinate and ‘-’ y – coordinate. E.g. (-3, -5)

IV Quadrant: ‘+’ x – coordinate and ‘-’ y – coordinate. E.g. (6, -1)

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Plotting on a Graph

Using the coordinate axes, we can describe any point in the plane using an ordered pair of numbers. A point A is represented by an ordered pair (xy) where x is the abscissa and y is the ordinate of the point.

Coordinate Geometry class 9-2

Position of a point in a plane

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Plotting a Point in the Plane if its Coordinates are Given

The coordinate points will define the location in the cartesian plane. The distance of a point from the y – axis is known as x-coordinate, or abscissa, and the distance of the point from the x-axis is known as y-coordinate, or ordinate.
For example, Point (3, 2) is 3 units away from the positive y-axis and 2 units away from the positive x-axis. Therefore, a point (3, 2) can be plotted below. Similarly, (-2, 3), (-1, -2) and (2, -3) are plotted.

Coordinate Geometry class 9-3

Plotting a point in the plane

Solved Example on Class 9 Maths Chapter 3 Coordinate Geometry

Example:

Each of the coordinates (-2, 4),(3, -1), (-1, 0),(1, 2), and (-3, -5) lies in which quadrant or on which axis? Locate them on the Cartesian plane to verify your solution.

Solution:

Negative abscissa and positive ordinate characterize the point (-2, 4).

(-2,4) is located in the second quadrant.

Positive abscissa and negative ordinate characterize the position (3, -1).

(3, -1) is located in the fourth quadrant.

Negative abscissa and zero ordinate characterize the point (-1, 0).

∴ On the negative x-axis is the point (-1, 0).

The abscissa and ordinate are both positive at points (1, 2).

∴ The first quadrant contains points (1,2).

Both the abscissa and ordinate are negative at the location (-3, -5).

∴ The 3rd quadrant contains the point (-3, -5).

These points are represented in the Cartesian plane as A(-2, 4), B(3, -1), C(-l, 0), D(l, 2), and E (-3, -5), as shown in the diagram.

Coordinate Geometry Class 9 Example

Also Access:
CBSE Class 9 Maths Chapter 2 Polynomial Notes
CBSE Class 9 Maths Chapter 4 Linear Equations in Two Variables Notes
NCERT Solutions for Class 9 Maths Chapter 3 Coordinate Geometry
NCERT Exemplar Class 9 Maths Solutions for Chapter 3 Coordinate Geometry
RD Sharma Solutions for Class 9 Maths Chapter 11 Coordinate Geometry
Quiz on Coordinate Geometry Class 9

9 Comments

  1. very good

  2. Thanks, it helped a lot

  3. This helps so much.
    Because we cannot find lot more deeper explanation and class notes anywhere.
    This helps me very much .
    Thank you byjus.

  4. thanks! it helped me in my school notes and in my exam too
    really very helpful!

  5. thank you. this was useful

  6. thank you it was really useful.

  7. Very nice Deeply explained
    Helped a lot

  8. It is usefull for me and maximum I will use Byju’s for my exams, it is so helpful ,thanks to Byju’s

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