# NCERT Solutions for Class 11 Maths Chapter 12 Introduction to Three Dimensional Geometry (Ex 12.1) Exercise 12.1

## NCERT Solutions for Class 11 Maths Chapter 12 Introduction to Three Dimensional Geometry (Ex 12.1) Exercise 12.1

Class 11 Maths NCERT Solutions Chapter 12 Ex 12.1 consistes of all the answers for the chapters of NCERT Class 11 paper - Three Dimensional Geometry. The Exercise 12.1 Class 11 solutions  are prepared by some of the best educators in the country. These solutions are simple and ideal for studying. These solutions provide you with a detailed explanation of the entire chapter. You can start your preparation by downloading the Exercise 12.1 Class 11 Maths Solution PDF.

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## Access NCERT Solutions for Class 11 Maths Chapter 12 - Introduction to Three Dimensional Geometry

Exercise 12.1

Refer to pages 1-3 for exercise 12.1 in the PDF

1. A point is on the x-axis. What are its y-coordinate and z-coordinates?

Ans: We know that, the coordinates of any point on the $x$-axis will be as $\left( {x,0,0} \right)$.

Thus, if a point is on the $x$-axis, then its $y$-coordinate will be $0$ and $z$-coordinate will be 0.

2. A point is in the XZ-plane. What can you say about its y-coordinate?

Ans: We know that, the coordinates of any point in the XZ-plane will be as $\left( {x,0,z} \right)$.

So, in the XZ- plane $y = 0$.

Thus, if a point is in the XZ- plane then the coordinate of $y$will always be 0.

Hence, its $y$-coordinate is 0.

3. Name the octants in which the following points lie:

$\left( {{\mathbf{1,2,3}}} \right)$

Ans: We have the following table,

 Octant Coordinates I II III IV V VI VII VIII $x$ + - - + + - - + $y$ + + - - + + - - $z$ + + + + - - - -

From the above table, the point $\left( {1,2,3} \right)$ lies in the first octant.

$\left( {{\mathbf{4, - 2,3}}} \right)$

Ans: We have the following table,

 Octant Coordinates I II III IV V VI VII VIII $x$ + - - + + - - + $y$ + + - - + + - - $z$ + + + + - - - -

From the above table, the point $\left( {4, - 2,3} \right)$ lies in octant IV.

$\left( {{\mathbf{4, - 2, - 5}}} \right)$

Ans: We have the following table,

 Octant Coordinates I II III IV V VI VII VIII $x$ + - - + + - - + $y$ + + - - + + - - $z$ + + + + - - - -

From the above table, the point $\left( {4, - 2, - 5} \right)$ lies in octant VIII.

$\left( {{\mathbf{4,2, - 5}}} \right)$

Ans: We have the following table,

From the above table, the point $\left( {4,2, - 5} \right)$ lies in octant V.

$\left( {{\mathbf{ - 4,2, - 5}}} \right)$

Ans: We have the following table,

 Octant Coordinates I II III IV V VI VII VIII $x$ + - - + + - - + $y$ + + - - + + - - $z$ + + + + - - - -

From the above table, the point $\left( { - 4,2, - 5} \right)$ lies in octant VI.

$\left( {{\mathbf{ - 4,2,5}}} \right)$

Ans: We have the following table,

 Octant Coordinates I II III IV V VI VII VIII $x$ + - - + + - - + $y$ + + - - + + - - $z$ + + + + - - - -

From the above table, the point $\left( { - 4,2,5} \right)$ lies in octant II.

$\left( {{\mathbf{ - 3, - 1,6}}} \right)$

Ans: We have the following table,

 Octant Coordinates I II III IV V VI VII VIII $x$ + - - + + - - + $y$ + + - - + + - - $z$ + + + + - - - -

From the above table, the point $\left( { - 3, - 1,6} \right)$ lies in octant III.

$\left( {{\mathbf{ - 2, - 4, - 7}}} \right)$

Ans: We have the following table,

 Octant Coordinates I II III IV V VI VII VIII $x$ + - - + + - - + $y$ + + - - + + - - $z$ + + + + - - - -

From the above table, the point $\left( { - 2, - 4, - 7} \right)$ lies in octant VII.

4. Fill in the blanks:

(i) The x-axis and y-axis taken together determine a plane known as ___________ .

Ans:  In XY-plane, $z = 0$.

Hence, the $x$-axis and $y$-axis taken together determine a plane known as XY-plane.

(ii) The coordinates of points in the XY-plane are of the form _____________ .

Ans: In XY-plane, $z = 0$.

Let $x$-coordinate be $x$ and $y$-coordinate be $y$.

Hence, the coordinates of points in the XY-plane are of the form $\left( {x,y,0} \right)$.

(iii) Coordinate planes divide the space into ______ octants.

Ans: Coordinate planes divide the space into 8 octants.

## CBSE Solutions for Class 11 Maths Chapter 12 - Introduction to Three Dimensional Geometry Exercise 12.1

The Class 11th Maths Chapter 12 Exercise 12.1 NCERT Solution is prepared by top teachers with years of teaching experience. These experienced teachers know exactly what is needed and they have prepared the notes exactly. They are subject-matter experts and they know which are the most important focus points. Furthermore, they are very well acquainted with the teacher's psychology. As a result, a vast majority of the question paper are already covered in this Exercise 12.1 Class 11 notes. This note is prepared as per the CBSE guidelines and everything in the syllabus is covered in this note.

There are no rewards for guessing the fact that Class 11 Maths syllabus is gigantic and there are a plethora of things to cover. From Determinants to Derivatives, from Conics to Boolean Algebra, the syllabus is vast and is equally concept-oriented. There are so many things to cover but you only have a limited time. This is where NCERT Solutions  come into the picture. Notes such as Exercise 12.1 Class 11 Maths NCERT Solutions will provide you the perfect base for going forward.

Talking of the importance of CBSE Class 11 Maths syllabus, the first thing that comes to mind is Three Dimensional Geometry. This is perhaps one of the most essential  chapters in the syllabus. This Chapter will put your application and conceptual understanding at test. This is why one of the main priorities was to make all the concepts clear. The NCERT Class 11 Maths Chapter 12 Exercise 12.1 specially focus on making the concepts clear with step-by-step solutions.

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Some Useful Education Tips to Score Good Marks in Maths

Class 11 means that you are standing at the most pivotal part of your career. You are just a step away from the Class 12 exam. The scores you obtain now will stay with you forever. This is why it is of utmost importance to lay maximum focus. For a subject like Maths, you need to concentrate, understand, and practice. There is no denying the fact that Maths is one of the most feared subjects. The term Maths phobia or Mathematical anxiety is very common among Class 11 students. At the same time, Maths is one of the most scoring subjects.

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• Plan Your Day - The NCERT Class 11 syllabus is humongous. However, you cannot afford to score excellent in a particular subject only. The board result will showcase the aggregate marks of all the subjects. As a result, you cannot spend an entire day studying English or practicing Maths. This is why you need to break your day into several parts and make the most of the available time.

• Understanding First - Maths is a subject which is entirely concept-based. You can certainly score excellent marks if your concepts are clear. This is why understanding not learning should always be the first priority. The Class 11 Ch 12 Ex 12.1 Maths NCERT Solutions is solely focused on bolstering your concepts with a focus on clear understanding.

• Practice Matters -  Regular practice is very important. You can practice the same sums but every time you will be learning something new. This is what practice does when it comes to a concept-oriented subject such as Maths. Practice regularly to strengthen your base. Chapters like Three Dimensional Geometry is entirely practice-oriented and it is exactly what you need for improving the base. When it comes to practice, you need the best notes. This is where NCERT Solutions Class 11 Maths Chapter 12 Ex 12.1 comes into the frame. Consult the notes created by the experts and start practicing.

• Solve Mocks - Practice papers are very important. Keep solving mock papers and previous years papers to get a clear grip. It will certainly help you to keep calm and boost your confidence. This will certainly take your exam preparation to the next level in a matter of time.

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