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Three Dimensional Geometry

Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.

Direction cosines and direction ratios of a line

Subtopic

Direction cosines and direction ratios of a line under Three Dimensional Geometry for Grade 12 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Which of the following lines is parallel to the line with direction ratios (1,2,3)(1, -2, 3)?

    A.

    A line with DRs (2,4,6)(2, -4, 6)

    B.

    A line with DRs (1,2,3)(1, 2, 3)

    C.

    A line with DRs (1,2,3)(-1, -2, -3)

    D.

    A line with DRs (3,2,1)(3, 2, 1)

  2. 2.

    If (a,b,c)(a, b, c) are direction ratios of a line, then which of the following is also a set of direction ratios for the same line?

    A.

    (a+1,b+1,c+1)(a+1, b+1, c+1)

    B.

    (a2,b2,c2)(a^2, b^2, c^2)

    C.

    (ka,kb,kc)(ka, kb, kc) for k0k \neq 0

    D.

    None of these

  3. 3.

    If a point PP is at a distance rr from the origin and the direction cosines of OPOP are (l,m,n)(l, m, n), then the xx-coordinate of PP is:

    A.

    l/rl/r

    B.

    r/lr/l

    C.

    lrlr

    D.

    l+rl+r

Download the worksheet for Three Dimensional Geometry - Direction cosines and direction ratios of a line to practice offline. It includes additional chapter-level practice questions.

Cartesian equation and vector equation of a line

Subtopic

Cartesian equation and vector equation of a line under Three Dimensional Geometry for Grade 12 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    If (12,12,n)(\frac{1}{2}, \frac{1}{2}, n) are the direction cosines of a line, then the value of nn is:

    A.

    12\frac{1}{\sqrt{2}}

    B.

    12\frac{1}{2}

    C.

    0

    D.

    1

  2. 2.

    What is the direction ratio of a line passing through (2,3,4)(2, 3, 4) and (5,6,7)(5, 6, 7)?

    A.

    (1, 1, 1)

    B.

    (2, 3, 4)

    C.

    (5, 6, 7)

    D.

    (7, 9, 11)

  3. 3.

    Find the direction ratios of the line x23=2y1=z\frac{x-2}{3} = 2y-1 = z.

    A.

    (3, 0.5, 1)

    B.

    (3, 2, 1)

    C.

    (3, 1, 1)

    D.

    (2, 1, 1)

Download the worksheet for Three Dimensional Geometry - Cartesian equation and vector equation of a line to practice offline. It includes additional chapter-level practice questions.

Coplanar and skew lines, shortest distance between two lines

Subtopic

Coplanar and skew lines, shortest distance between two lines under Three Dimensional Geometry for Grade 12 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    If two lines are r=a1+λb1\vec{r} = \vec{a}_1 + \lambda \vec{b}_1 and r=a2+μb2\vec{r} = \vec{a}_2 + \mu \vec{b}_2, the vector representing the displacement between points on the two lines is generally:

    A.

    b1×b2\vec{b}_1 \times \vec{b}_2

    B.

    a2a1\vec{a}_2 - \vec{a}_1

    C.

    (a2+μb2)(a1+λb1)(\vec{a}_2 + \mu \vec{b}_2) - (\vec{a}_1 + \lambda \vec{b}_1)

    D.

    b1\vec{b}_1

  2. 2.

    The direction ratios of a line passing through (0,0,0)(0,0,0) and (1,2,3)(1,2,3) are:

    A.

    (1, 0, 0)

    B.

    (1, 2, 3)

    C.

    (0, 0, 0)

    D.

    (2, 4, 6)

  3. 3.

    Find the shortest distance between the lines x=1,y=1x=1, y=1 and x=4,y=5x=4, y=5 in 3D.

    A.

    3 units

    B.

    4 units

    C.

    5 units

    D.

    0 units

Download the worksheet for Three Dimensional Geometry - Coplanar and skew lines, shortest distance between two lines to practice offline. It includes additional chapter-level practice questions.

Cartesian and vector equation of a plane

Subtopic

Cartesian and vector equation of a plane under Three Dimensional Geometry for Grade 12 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    The equation of the plane passing through (2,3,4)(2, 3, 4) and perpendicular to the zz-axis is:

    A.

    z=4z = 4

    B.

    x=2x = 2

    C.

    y=3y = 3

    D.

    z=0z = 0

  2. 2.

    The vector equation of the plane 3x4z=123x - 4z = 12 is:

    A.

    r(3i^4k^)=12\vec{r} \cdot (3\hat{i} - 4\hat{k}) = 12

    B.

    r(3i^+4j^)=12\vec{r} \cdot (3\hat{i} + 4\hat{j}) = 12

    C.

    r(3i^4j^)=12\vec{r} \cdot (3\hat{i} - 4\hat{j}) = 12

    D.

    r(3i^+4k^)=12\vec{r} \cdot (3\hat{i} + 4\hat{k}) = 12

  3. 3.

    If a plane passes through (k,0,0)(k, 0, 0), (0,k,0)(0, k, 0), and (0,0,k)(0, 0, k), its equation is:

    A.

    x+y+z=kx + y + z = k

    B.

    x+y+z=1x + y + z = 1

    C.

    x+y+z=3kx + y + z = 3k

    D.

    kx+ky+kz=1kx + ky + kz = 1

Download the worksheet for Three Dimensional Geometry - Cartesian and vector equation of a plane to practice offline. It includes additional chapter-level practice questions.

Angle between two lines, two planes, a line and a plane

Subtopic

Angle between two lines, two planes, a line and a plane under Three Dimensional Geometry for Grade 12 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    The sine of the angle between the plane x+y+z=1x + y + z = 1 and the line joining (0,0,0)(0,0,0) and (1,2,3)(1,2,3) is:

    A.

    67\sqrt{\frac{6}{7}}

    B.

    57\sqrt{\frac{5}{7}}

    C.

    67\frac{6}{7}

    D.

    17\frac{1}{\sqrt{7}}

  2. 2.

    If A(1,0,0)A(1,0,0), B(0,1,0)B(0,1,0), and C(0,0,1)C(0,0,1) are points, the angle between the lines ABAB and ACAC is:

    A.

    3030^{\circ}

    B.

    4545^{\circ}

    C.

    6060^{\circ}

    D.

    9090^{\circ}

  3. 3.

    The angle between the planes x=2x = 2 and y=3y = 3 is:

    A.

    00^{\circ}

    B.

    4545^{\circ}

    C.

    9090^{\circ}

    D.

    180180^{\circ}

Download the worksheet for Three Dimensional Geometry - Angle between two lines, two planes, a line and a plane to practice offline. It includes additional chapter-level practice questions.

Distance of a point from a plane

Subtopic

Distance of a point from a plane under Three Dimensional Geometry for Grade 12 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Find the distance of the point (3,4,5)(3, 4, 5) from the plane 2xy+2z=32x - y + 2z = 3.

    A.

    33

    B.

    11

    C.

    99

    D.

    22

  2. 2.

    Find the distance of the point (1,1,1)(1, 1, 1) from the plane 4x+3y+12z=64x + 3y + 12z = 6.

    A.

    11

    B.

    1313

    C.

    1/131/13

    D.

    00

  3. 3.

    The distance of the point (4,2,3)(4, -2, 3) from the plane 2x2y+z=52x - 2y + z = 5 is:

    A.

    10/310/3

    B.

    55

    C.

    33

    D.

    15/315/3

Download the worksheet for Three Dimensional Geometry - Distance of a point from a plane to practice offline. It includes additional chapter-level practice questions.

Three Dimensional Geometry - Class 12 Maths (CBSE) | Krit.club