Coordinate Geometry| NCERT Solutions| Class 9

NCERT Solutions of  Chapter: Coordinate Geometry. NCERT Solutions along with worksheets and notes for Class 9.

Exercise 3.1

(1) How will you describe the position of a table lamp on your study table to another person?

Ans-

To describe position of the table lamp on my table, we must know its coordinates.

Assume long edges is x -axis and short edges is y-axis.

Now, measure distance from x- axis to lamp is 15cm.

Measure distance from y – axis to lamp is 10 cm.

Therefore, coordinates of the lamp are (15, 10).

 

(2) (Street Plan): A city has two main roads which cross each other at the centre of the city. These two roads are along the North – South direction and East – West direction. All the other streets of the city run parallel to these roads and are 200 m apart. There are 5 streets in each direction. Use 1 cm = 200 m to draw a model of the city on your notebook. Represent the roads/ streets by single lines.

There are many cross – streets in your model. A particular cross – street is made by two streets, one running in the North – South direction and another in the East- West direction. Each cross street is referred to in the following manner: If the 2nd street running in the North – South direction and 5th in the East – West direction meet at some crossing, then we will call this cross – street(2, 5). Using this convention, find:

(i) how many cross – streets can be referred to as(4,3).

(ii) how many cross – streets can be referred to as (3, 4).

Ans-

Street plan is shown below using scale of 200 m = 1 cm.

Diagram of Question 2 of Exercise 3.1 of NCERT Chapter Coordinate Geometry

(i) Only one cross street can be referred as (4, 3).

(ii) Only one cross street can be referred as (3, 4).

 

Exercise 3.2

(1) Write the answer of each of the following questions:

(i) What is the name of horizontal and the vertical lines drawn to determine the position of any point in the Cartesian plane?

(ii) What is the name of each part of the plane formed by these two lines?

(iii) Write the name of the point where these two lines intersect.

Ans-

(i) The horizontal line is known as x – axis and vertical line is known as y- axis which are drawn to determine the position of any point in the Cartesian plane.

(ii) The parts of the plane formed by these two lines are called as quadrant I, quadrant II, quadrant III and quadrant IV.

(iii) These two lines intersect each other at origin.

 

(2) See fig given below and write the following:

(i) The coordinates of B.

(ii) The coordinates of C.

(iii) The point identified by the coordinates (-3, -5).

(iv)The point identified by the coordinates (2, – 4).

(v) The abscissa of the point D.

(vi) The ordinate of the point H.

(vii) The coordinates of the point L.

(viii) The coordinates of the point M.

Diagram of Question 2 of Exercise 3.2 of NCERT Chapter Coordinate Geometry

Ans-

(i) The coordinates of point B are (-5, 2).

(ii) The coordinates of point C are (5, – 5).

(iii) The point identified by the coordinates (-3, -5) is E.

(iv)The point identified by the coordinates (2, – 4) is G.

(v) The abscissa of the point D is 6.

(vi) The ordinate of the point H is – 3.

(vii) The coordinates of the point L are (0, 5).

(viii) The coordinates of the point M are (-3, 0).

 

Exercise 3.3

(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.

Ans-

(-2, 4) will lie in quadrant II because x coordinate is negative and y coordinate is positive.

The point is locating on Cartesian plane below-

 

Diagram of Question 1 of Exercise 3.3 of NCERT Chapter Coordinate Geometry

(3, -1) will lie in quadrant IV because x coordinate is positive and y coordinate is negative.

The point is locating on Cartesian plane below-

Diagram of Question 1 of Exercise 3.3

(-1, 0) will lie on x – axis because x coordinate is negative and y coordinate is zero.

The point is locating on Cartesian plane below-

 

Diagram of Question 1 of Exercise 3.3

(1, 2) will lie in quadrant I because x coordinate is positive and y coordinate is also positive.

The point is locating on Cartesian plane below-

Diagram of Question 1 of Exercise 3.3

(-3, -5) will lie in quadrant III because x coordinate is negative and y coordinate is also negative.

The point is locating on Cartesian plane below-

Diagram of Question 1 of Exercise 3.3

 

(2) Plot the points (x, y) given in the following table on the plane, choosing suitable units of distance on the axes.

x -2 -1 0 1 3
y 8 7 -1.25 3 -1

Ans-

Plotting all points on the plane by using scale of 1 cm = 1 unit.

Diagram of Question 2 of Exercise 3.3 of NCERT Chapter Coordinate Geometry

Helping Points

Coordinate Geometry

Worksheet Class 9

 

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