NCERT Solutions for Class 9 Maths Chapter 3 Coordinate Geometry Ex 3.1

# NCERT Solutions for Class 9 Maths Chapter 3 Coordinate Geometry Ex 3.1

NCERT Solutions for Class 9 Maths Chapter 3 Coordinate Geometry Ex 3.1 are the part of NCERT Solutions for Class 9 Maths. In this post, you will find the NCERT Solutions for Class 9 Maths Chapter 3 Coordinate Geometry Ex 3.1.

## NCERT Solutions for Class 9 Maths Chapter 3 Coordinate Geometry Ex 3.1

Ex 3.1 Class 9 Maths Question 1.
How will you describe the position of a table lamp on your study table to another person?

Solution:
To describe the position of a table lamp placed on the table, let us consider the table lamp as P and the table as a plane.
Now, take two mutually perpendicular edges of the table as the axes OX and OY.
Measure the perpendicular distance ‘a’ cm of P (lamp) from OY and the perpendicular distance ‘b’ cm of P (lamp) from OX.
Thus, the position of the table lamp P is described by the ordered pair (a, b).

Let us assume that the distance of lamp from OY is 18 cm and the distance of lamp from OX is 16 cm. Then the position of the lamp can be described as the ordered pair (18, 16).

Ex 3.1 Class 9 Maths Question 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 other streets of the city run parallel to these roads and are 200 m apart. There are 5 streets in each direction. Using 1 cm = 200 m, 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).

Solution:

Let us draw two mutually perpendicular lines as the two main roads of the city that cross each other at the centre and let us take it as N-S and E-W direction.

Let us use the scale as 1 cm = 200 m.

Now, draw five streets that are parallel to both the main roads, to get the given below figure.

(i)
From the figure, we can see that only one point has the coordinates as (4, 3). Thus, we can conclude that only one cross street can be referred to as A(4, 3).
(ii) From the figure, we can see that only one point has the coordinates as (3, 4). Thus, we can conclude that only one cross street can be referred to as B(3, 4).