NCERT Solutions · Class 12

NCERT Solutions for Class 12 Maths Chapter 11 Three Dimensional Geometry — Exercise 11.20

Step-by-step NCERT Solutions for Class 12 Maths Chapter 11 (Three Dimensional Geometry), Exercise 11.20. 23 questions with answers — read online free on NCERT Help.

Maths Chapter 11 Exercise 11.20 23 questions
ClassClass 12
SubjectMaths
ChapterChapter 11 — Three Dimensional Geometry
ExerciseExercise 11.20
Questions solved23

Exercises in this chapter

Questions & step-by-step answers

Question 1:Show that the line joining the origin to the point (2, 1, 1) is perpendicular to the line determined by the points (3, 5, – 1), (4, 3, – 1).

Question 2:If l 1 , m1 , n1 and l 2 , m2 , n2 are the direction cosines of two mutually perpendicular lines, show that the direction cosines of the line perpendicular to both of these are 1 2 2 1 12 21 1 2 2 1 m n m n nl n

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Question 3:Find the angle between the lines whose direction ratios are a, b, c and b – c, c – a, a – b.

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Question 4:Find the equation of a line parallel to x-axis and passing through the origin.

Question 5:If the coordinates of the points A, B, C, D be (1, 2, 3), (4, 5, 7), (– 4, 3, – 6) and (2, 9, 2) respectively, then find the angle between the lines AB and CD.

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Question 6:If the lines 1 23 1 1 6 and 32 2 3 1 5 x y z xy z k k are perpendicular, find the value of k.

Question 7:Find the vector equation of the line passing through (1, 2, 3) and perpendicular to the plane ) 9 0 ˆ r (. i ˆ 2 ˆj 5 k .

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Question 8:Find the equation of the plane passing through (a, b, c) and parallel to the plane ˆ ˆ ˆ ri jk ( ) 2.

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Question 9:Find the shortest distance between lines ˆˆ ˆ ˆ ˆ ˆ ri j k i j k 6 2 2 ( 2 2) and r i 4 ( ˆ ˆ k i jk ˆ ˆ 3 2 ˆ 2 ) .

Question 10:Find the coordinates of the point where the line through (5, 1, 6) and (3, 4,1) crosses the YZ-plane.

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Question 11:Find the coordinates of the point where the line through (5, 1, 6) and (3, 4, 1) crosses the ZX-plane.

Question 12:Find the coordinates of the point where the line through (3, – 4, – 5) and (2, – 3, 1) crosses the plane 2x + y + z = 7.

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Question 13:Find the equation of the plane passing through the point (– 1, 3, 2) and perpendicular to each of the planes x + 2y + 3z = 5 and 3x + 3y + z = 0.

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Question 14:If the points (1, 1, p) and (– 3, 0, 1) be equidistant from the plane ˆ ˆ ˆ (3 4 12 ) 13 0, ri j k then find the value of p.

Question 15:Find the equation of the plane passing through the line of intersection of the planes ˆ ˆ ˆ ri jk ( ) 1 and ˆ ˆ ˆ r i jk (2 3 ) 4 0 and parallel to x-axis.

1. Show that the line joining the origin to the po

Question 16:If O be the origin and the coordinates of P be (1, 2, – 3), then find the equation of the plane passing through P and perpendicular to OP.

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Question 17:Find the equation of the plane which contains the line of intersection of the planes ˆ ˆ ˆ ri j k ( 2 3) 4 0 , ˆ ˆ ˆ r i jk (2 ) 5 0 and which is perpendicular to the plane ˆ ˆ ˆ ri jk (5 3 6 ) 8 0

Question 18:Find the distance of the point (– 1, – 5, – 10) from the point of intersection of the line ˆˆ ˆ ˆ ˆ ˆ r ij k i j k 2 2( 3 4 2 ) and the plane ˆ ˆ ˆ ri jk ( ) 5 .

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Question 19:Find the vector equation of the line passing through (1, 2, 3) and parallel to the planes ˆ ˆ ˆ ri j k ( 2 ) 5 and ˆ ˆ ˆ r i jk (3 ) 6 .

Question 20:Find the vector equation of the line passing through the point (1, 2, – 4) and perpendicular to the two lines: 7 10 16 19 3 8 x y z and 15 3 x = 29 5 8 5 y z .

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Question 21:Prove that if a plane has the intercepts a, b, c and is at a distance of π units from the origin, then 2 2 2 2 1 1 1 1 a b c p . Choose the correct answer in Exercises 22 and 23

CBSE NCERT Solutions For Class 12 Three Dimensional Geometry

Question 22:Distance between the two planes: 2x + 3y + 4z = 4 and 4x + 6y + 8z = 12 is (A) 2 units (B) 4 units (C) 8 units (D) 2 29 units

Question 23:The planes: 2x – y + 4z = 5 and 5x – 2.5y + 10z = 6 are (A) Perpendicular (B) Parallel (C) intersect y-axis (D) passes through 5 0,0, 4

About this exercise

ncert solutions for class 12 Math Chapter 11 Miscellaneous

Frequently asked questions

Where can I read NCERT Solutions for Class 12 Maths Exercise 11.20?

You can read step-by-step NCERT Solutions for Class 12 Maths Chapter 11 Exercise 11.20 online on NCERT Help at this page — no download required.

How many questions are solved in Exercise 11.20?

This page includes 23 NCERT textbook questions with detailed answers.

What are the other exercises in this chapter?

Browse all exercises for Class 12 Maths Chapter 11 using the exercise switcher on this page or the full chapter list on the subject hub.