NCERT Class 9 Maths Solutions Chapter - 3 Coordinate Geometry, Ex - 3.3

Ex - 3.3

Question 1.  In which quadrant or on which axis do each of the points (-2,4), (3,-1), (-1,0), (1,2) and (-3,-5)  lie? Verify your answer by locating them on the Cartesian plane.

Solution

(i) The point (-2,4) lies in IInd quadrant in Cartesian plane as for  point (-2,4), x coordinate is negative and y coordinate is positive.

(ii) The point (3,-1) lies in IVth quadrant in Cartesian plane because for point (3,-1) , x coordinate is positive and y coordinate is negative.

(iii) The point (-1,0) lies on negative x-axis because for point (-1,0)  the value of y coordinate is zero and the value of x coordinate is negative.

(iv) The point (1,2) lies in Ist quadrant as for point (1,2)  both x and y are positive 

(v) The point (-3,-5) lies in the IIIrd quadrant in Cartesian plane as for point (-3,-5) both x and y are negative.

Now let's plot each of the above points on the coordinate plane.

Concept Insight:- 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. The coordinates of any point on the x axis has y coordinate as zero and for a point on y axis x coordinate is zero.
 For plotting the points let say (3,4) start from the origin first move 3 units along positive x axis and then from this marked position move 4 units along  positive y axis.

Question 2.  Plot the point (x, y) given in the following table on the plane, choosing suitable units of distance on the axis.
x
-2
-1
0
1
3
y
8
7
-1.25
3
-1

Solution

 The given points are plotted on the Cartesian plane as below:
Concept Insight: The coordinates of a point (x,y) is such that its distance from y axis along the positive x axis is x units and the distance of the point from x axis along the y axis is y units. To locate such point we need to start from origin, count x units along x axis and then further move y units along y axis.


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