Ex 1.1 Class 9 Ganita Manjari Chapter 1: Orienting Yourself: The Use of Coordinates

Class 9 Maths Ganita Manjari Chapter 1 Exercise 1.1 Solutions

1: Figure shows Reiaan’s room with points OABC marking its corners. The x- and y-axes are marked in the figure. Point O is the origin.

Referring to Figure, answer the following questions:

(i) If D₁ R₁ represents the door to Reiaan’s room, how far is the door from the left wall (the y-axis) of the room? How far is the door from the x-axis?

Answer: 

From the figure, the door

$D_1{R}_1$

lies between

$x=8$

and

$x=9$

, and on the x-axis (

$y=0$

).

Therefore:

• Distance from the left wall (y-axis): 8 units
• Distance from the x-axis: 0 units

The door is 8 units from the left wall and 0 units from the x-axis.

(ii)  What are the coordinates of D₁?

Answer: 

From the figure,

$D_1$is located at

$x=8$

on the x-axis, so its coordinates are:

D1​=(8,0)

​(iii)  If R₁ is the point (11.5, 0), how wide is the door? Do you think this is a comfortable width for the room door? If a person in a wheelchair wants to enter the room, will he/she be able to do so easily?

Answer: 

Given:

• D1=(8,0)
• R1=(11.5,0)

The width of the door is the distance between these two points:

$$11.5-8=3.5\text{units}$$

So, the door is 3.5 units wide.

Yes, this is a comfortable width for a room door. A person using a wheelchair should also be able to enter easily, as the doorway provides sufficient space for wheelchair access.

(iv)  If B₁ (0, 1.5) and B₂ (0, 4) represent the ends of the bathroom door, is the bathroom door narrower or wider than the room door?

Answer: 

Given:

• B1=(0,1.5)
• B2=(0,4)

Bathroom door width:

$$4-1.5=2.5\text{units}$$

Room door width =

$3.5$units.

Since

$2.5<3.5$

The bathroom door is narrower than the room door.