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Three Dimensional Geometry · Question 37

JEE Main 2025 (Online) 7th April Evening ShiftMCQMedium📈 Topic in 35% papers+4−1
1

If the equation of the line passing through the point (0, - 12, 0 ) and perpendicular to the lines r = ( i + a j + b k ) and r = ( i - j - 6 k ) + (-b i + a j + 5 k ) is x-1-2 = y+4d = z-c-4, then a + b + c + d is equal to :

  1. 13
  2. 14
  3. 12
  4. 10

Answer

(2) 14

Solution

The point (0, - 12, 0 ) lies on x-1-2 = y+4d = z-c-4:

0-1-2 = 12 - 12+4d = 12 d = 7 and -c-4 = 12 c = 2

Direction ratios of the line: (-2, 7, -4)

Perpendicular to (1, a, b): -2 + 7a - 4b = 0 ...(i)

Perpendicular to (-b, a, 5): 2b + 7a - 20 = 0 ...(ii)

(ii) − (i): 6b - 18 = 0 b = 3, then 7a = 14 a = 2

a + b + c + d = 2 + 3 + 2 + 7 = 14

Answer: (2)

JEE Main 2025 (Online) 7th April Evening Shift

Keep practising — Three Dimensional Geometry

2

Consider the lines L1: x - 1 = y - 2 = z and L2: x - 2 = y = z - 1. Let the feet of the perpendiculars from the point P(5, 1, -3) on the lines L1 and L2 be Q and R respectively. If the area of the triangle PQR is A, then 4A2 is equal to :

  1. 151
  2. 147
  3. 139
  4. 143
JEE Main 2025 (Online) 7th April Evening Shift
3

Let the shortest distance between the lines x-33 = y- -1 = z-31 and x+3-3 = y+72 = z- 4 be 3 30. Then the positive value of 5 + is

  1. 42
  2. 40
  3. 48
  4. 46
JEE Main 2025 (Online) 4th April Morning Shift
4

Let A and B be two distinct points on the line L : x - 63 = y - 72 = z - 7-2. Both A and B are at a distance 2 17 from the foot of perpendicular drawn from the point (1, 2, 3) on the line L. If O is the origin, then OA OB is equal to

  1. 49
  2. 21
  3. 47
  4. 62
JEE Main 2025 (Online) 4th April Morning Shift
5

Let A be the point of intersection of the lines L1: x-71= y-50= z-3-1 and L2: x-13= y+34= z+75. Let B and C be the points on the lines L1 and L2 respectively such that AB=AC= 15. Then the square of the area of the triangle ABC is :

  1. 63
  2. 57
  3. 60
  4. 54
JEE Main 2025 (Online) 4th April Evening Shift
6

Let the values of p, for which the shortest distance between the lines x+13= y4= z5 and r=(p i+2 j+ k)+ (2 i+3 j+4 k) is 1 6, be a, b, (a<b). Then the length of the latus rectum of the ellipse x2a2+ y2b2=1 is :

  1. 32
  2. 9
  3. 18
  4. 23
JEE Main 2025 (Online) 4th April Evening Shift
7

Let a line passing through the point (4, 1, 0) intersect the line L1 : x-12 = y-23 = z-34 at the point A( , , ) and the line L2 : x - 6 = y = -z + 4 at the point B(a, b, c). Then vmatrix 1 & 0 & 1 \ & & \ a & b & c vmatrix is equal to

  1. 16
  2. 6
  3. 8
  4. 12
JEE Main 2025 (Online) 3rd April Morning Shift
8

Line L1 passes through the point (1, 2, 3) and is parallel to z-axis. Line L2 passes through the point ( , 5, 6) and is parallel to y-axis. Let for = 1, 2, 2 < 1, the shortest distance between the two lines be 3. Then the square of the distance of the point ( 1, 2, 7) from the line L1 is

  1. 25
  2. 32
  3. 40
  4. 37
JEE Main 2025 (Online) 3rd April Morning Shift
9

Each of the angles and that a given line makes with the positive y- and z-axes, respectively, is half of the angle that this line makes with the positive x-axis. Then the sum of all possible values of the angle is

  1. 2
  2. 3 4
  3. 3 2
JEE Main 2025 (Online) 3rd April Evening Shift
10

The distance of the point (7, 10, 11) from the line x-41 = y-40 = z-23 along the line x-92 = y-133 = z-176 is

  1. 16
  2. 12
  3. 18
  4. 14
JEE Main 2025 (Online) 3rd April Evening Shift
11

Let the vertices Q and R of the triangle PQR lie on the line x+35 = y-12 = z+43, QR = 5 and the coordinates of the point P be (0, 2, 3). If the area of the triangle PQR is mn then :

  1. 2m - 5 21 n = 0
  2. m - 5 21 n = 0
  3. 5m - 21 2 n = 0
  4. 5m - 2 21 n = 0
JEE Main 2025 (Online) 2nd April Morning Shift

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