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Three-Dimensional Geometry

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

Direction Cosines and Ratios of a Line

Subtopic

Direction Cosines and Ratios of a Line under Three-Dimensional Geometry for Grade 12 ICSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Direction ratios of a line are also known as:

    A.

    Direction angles

    B.

    Direction numbers

    C.

    Direction coordinates

    D.

    Direction slopes

  2. 2.

    If the direction cosines of a line are (1c,1c,1c)(\frac{1}{c}, \frac{1}{c}, \frac{1}{c}), find the positive value of cc.

    A.

    11

    B.

    2\sqrt{2}

    C.

    3\sqrt{3}

    D.

    33

  3. 3.

    The sum of the squares of the direction ratios a,b,ca, b, c of a line is always equal to 1. Is this statement true or false?

    A.

    True

    B.

    False

    C.

    Only if the line passes through origin

    D.

    Only if the line is vertical

Download the worksheet for Three-Dimensional Geometry - Direction Cosines and Ratios of a Line to practice offline. It includes additional chapter-level practice questions.

Equation of a Line (Vector and Cartesian)

Subtopic

Equation of a Line (Vector and Cartesian) under Three-Dimensional Geometry for Grade 12 ICSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    A line passes through the point P(2,−3,4)P(2, -3, 4) and is parallel to the vector b⃗=3i^+2j^−5k^\vec{b} = 3\hat{i} + 2\hat{j} - 5\hat{k}. Which of the following represents the Cartesian equation of this line?

    A.

    x−23=y+32=z−4−5\frac{x - 2}{3} = \frac{y + 3}{2} = \frac{z - 4}{-5}

    B.

    x+23=y−32=z+4−5\frac{x + 2}{3} = \frac{y - 3}{2} = \frac{z + 4}{-5}

    C.

    x−32=y−2−3=z+54\frac{x - 3}{2} = \frac{y - 2}{-3} = \frac{z + 5}{4}

    D.

    x−23=y+32=z−45\frac{x - 2}{3} = \frac{y + 3}{2} = \frac{z - 4}{5}

  2. 2.

    Find the vector equation of a line passing through (2,3,2)(2, 3, 2) and parallel to the vector 3i^+2j^−8k^3\hat{i} + 2\hat{j} - 8\hat{k}.

    A.

    r⃗=(2i^+3j^+2k^)+λ(3i^+2j^−8k^)\vec{r} = (2\hat{i} + 3\hat{j} + 2\hat{k}) + \lambda(3\hat{i} + 2\hat{j} - 8\hat{k})

    B.

    r⃗=(3i^+2j^−8k^)+λ(2i^+3j^+2k^)\vec{r} = (3\hat{i} + 2\hat{j} - 8\hat{k}) + \lambda(2\hat{i} + 3\hat{j} + 2\hat{k})

    C.

    r⃗=(2i^−3j^−2k^)+λ(3i^+2j^−8k^)\vec{r} = (2\hat{i} - 3\hat{j} - 2\hat{k}) + \lambda(3\hat{i} + 2\hat{j} - 8\hat{k})

    D.

    r⃗=(3i^−2j^+8k^)+λ(2i^+3j^+2k^)\vec{r} = (3\hat{i} - 2\hat{j} + 8\hat{k}) + \lambda(2\hat{i} + 3\hat{j} + 2\hat{k})

  3. 3.

    Two lines with direction ratios (a1,b1,c1)(a_1, b_1, c_1) and (a2,b2,c2)(a_2, b_2, c_2) are parallel if:

    A.

    a1a2=b1b2=c1c2\frac{a_1}{a_2} = \frac{b_1}{b_2} = \frac{c_1}{c_2}

    B.

    a1a2+b1b2+c1c2=0a_1 a_2 + b_1 b_2 + c_1 c_2 = 0

    C.

    a1a2+b1b2+c1c2=1a_1 a_2 + b_1 b_2 + c_1 c_2 = 1

    D.

    a1=a2,b1=b2,c1=c2a_1 = a_2, b_1 = b_2, c_1 = c_2

Download the worksheet for Three-Dimensional Geometry - Equation of a Line (Vector and Cartesian) to practice offline. It includes additional chapter-level practice questions.

Shortest Distance between Skew Lines

Subtopic

Shortest Distance between Skew Lines under Three-Dimensional Geometry for Grade 12 ICSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    If the shortest distance between two lines is a non-zero value, and the direction vectors are not proportional, the lines are:

    A.

    Parallel

    B.

    Intersecting

    C.

    Skew

    D.

    Coincident

  2. 2.

    The lines r⃗=a⃗1+λb⃗1\vec{r} = \vec{a}_1 + \lambda \vec{b}_1 and r⃗=a⃗2+μb⃗2\vec{r} = \vec{a}_2 + \mu \vec{b}_2 are parallel. The distance dd is given by d=∣(a⃗2−a⃗1)×b⃗∣∣b⃗∣d = \frac{|(\vec{a}_2 - \vec{a}_1) \times \vec{b}|}{|\vec{b}|}. What does b⃗\vec{b} represent?

    A.

    The vector b⃗1+b⃗2\vec{b}_1 + \vec{b}_2

    B.

    The vector b⃗1×b⃗2\vec{b}_1 \times \vec{b}_2

    C.

    The common direction vector of the parallel lines

    D.

    The vector a⃗2−a⃗1\vec{a}_2 - \vec{a}_1

  3. 3.

    Which of the following describes the shortest distance between two skew lines?

    A.

    The length of the segment parallel to both lines.

    B.

    The length of the segment perpendicular to both lines.

    C.

    The distance between any two random points on the lines.

    D.

    The average of the distances from the origin to each line.

Download the worksheet for Three-Dimensional Geometry - Shortest Distance between Skew Lines to practice offline. It includes additional chapter-level practice questions.

Equation of a Plane (Vector and Cartesian)

Subtopic

Equation of a Plane (Vector and Cartesian) under Three-Dimensional Geometry for Grade 12 ICSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    What is the intercept of the plane r⃗⋅(2i^−j^+k^)=4\vec{r} \cdot (2\hat{i} - \hat{j} + \hat{k}) = 4 on the yy-axis?

    A.

    22

    B.

    −4-4

    C.

    44

    D.

    −2-2

  2. 2.

    Find the equation of the plane passing through the point (1,−1,2)(1, -1, 2) and parallel to the plane 3x+4y−5z=03x + 4y - 5z = 0.

    A.

    3x+4y−5z=113x + 4y - 5z = 11

    B.

    3x+4y−5z=−113x + 4y - 5z = -11

    C.

    3x+4y−5z=03x + 4y - 5z = 0

    D.

    3x−4y+5z=113x - 4y + 5z = 11

  3. 3.

    Two planes a1x+b1y+c1z+d1=0a_1x + b_1y + c_1z + d_1 = 0 and a2x+b2y+c2z+d2=0a_2x + b_2y + c_2z + d_2 = 0 are perpendicular if:

    A.

    a1a2+b1b2+c1c2=0a_1a_2 + b_1b_2 + c_1c_2 = 0

    B.

    a1a2=b1b2=c1c2\frac{a_1}{a_2} = \frac{b_1}{b_2} = \frac{c_1}{c_2}

    C.

    a1a2=b1b2=c1c2a_1a_2 = b_1b_2 = c_1c_2

    D.

    a1+a2=b1+b2=c1+c2a_1+a_2 = b_1+b_2 = c_1+c_2

Download the worksheet for Three-Dimensional Geometry - Equation of a Plane (Vector and Cartesian) to practice offline. It includes additional chapter-level practice questions.

Angle between Lines, Planes, and a Line and a Plane

Subtopic

Angle between Lines, Planes, and a Line and a Plane under Three-Dimensional Geometry for Grade 12 ICSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    The angle between the line x−11=y−22=z−32\frac{x-1}{1} = \frac{y-2}{2} = \frac{z-3}{2} and the zz-axis is:

    A.

    cos⁡−1(1/3)\cos^{-1}(1/3)

    B.

    cos⁡−1(2/3)\cos^{-1}(2/3)

    C.

    30∘30^\circ

    D.

    60∘60^\circ

  2. 2.

    What is the angle between the planes x+y+z=1x+y+z=1 and x−y+z=1x-y+z=1?

    A.

    cos⁡−1(1/3)\cos^{-1}(1/3)

    B.

    cos⁡−1(2/3)\cos^{-1}(2/3)

    C.

    60∘60^\circ

    D.

    90∘90^\circ

  3. 3.

    The angle between the lines x−57=y+2−5=z1\frac{x-5}{7} = \frac{y+2}{-5} = \frac{z}{1} and x1=y2=z3\frac{x}{1} = \frac{y}{2} = \frac{z}{3} is:

    A.

    0∘0^\circ

    B.

    45∘45^\circ

    C.

    90∘90^\circ

    D.

    60∘60^\circ

Download the worksheet for Three-Dimensional Geometry - Angle between Lines, Planes, and 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 ICSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    The distance of the point (2,3,4)(2, 3, 4) from the plane 3x−6y+2z+11=03x - 6y + 2z + 11 = 0 is:

    A.

    11 unit

    B.

    22 units

    C.

    33 units

    D.

    00 units

  2. 2.

    Calculate the distance of point (2,1,0)(2, 1, 0) from the plane 2x+y+2z+5=02x + y + 2z + 5 = 0.

    A.

    55 units

    B.

    33 units

    C.

    10/310/3 units

    D.

    44 units

  3. 3.

    The distance of the point (1,2,3)(1, 2, 3) from the plane x−y+z=5x - y + z = 5 is:

    A.

    33\frac{3}{\sqrt{3}}

    B.

    53\frac{5}{\sqrt{3}}

    C.

    3\sqrt{3}

    D.

    13\frac{1}{\sqrt{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.