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Three Dimensional Geometry · Question 2

JEE Main 2026 (Online) 8th April Evening ShiftNumericalMedium📈 Topic in 10% papers+4
1

Let a line L1 pass through the origin and be perpendicular to the lines L2 : r=(3+t) i+(2t-1) j+(2t+4) k and L3 : r=(3+2s) i+(3+2s) j+(2+s) k, t, s R. If (a, b, c), a Z, is the point on L3 at a distance of 17 from the point of intersection of L1 and L2, then (a+b+c)2 is equal to .

Answer

4

Solution

Directions: L2: (1, 2, 2), L3: (2, 2, 1)

L1 is perpendicular to both: vmatrix i & j & k\ 1 & 2 & 2\ 2 & 2 & 1 vmatrix=-2 i+3 j-2 k

1: (x, y, z)= (-2, 3, -2)

L1 2: 3+t=-2 , 2t-1=3 , 2t+4=-2

First and third 3+t=2t+4 t=-1, =-1 (second: -3=-3, true)

P(2, -3, 2)

Point of L3: Q(3+2s, 3+2s, 2+s); PQ2=17

(1+2s)2+(6+2s)2+s2=17 9s2+28s+20=0 (s+2)(9s+10)=0

s=- 109 gives a= 79 (rejected); s=-2 gives Q(-1, -1, 0)

a+b+c=-2 (a+b+c)2=4

Answer: 4

JEE Main 2026 (Online) 8th April Evening Shift

Keep practising — Three Dimensional Geometry

2

Let the image of the point P(1, 6, a) in the line L : x1= y-12= z-a+1b, b>0, be ( a3, 0, a+c ). If S( , , ), >0, is the point on L such that the distance of S from the foot of perpendicular from the point P on L is 2 14, then + + is equal to :

  1. 19
  2. 20
  3. 21
  4. 22
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3

Let a line L be perpendicular to both the lines L1 : x+13= y+35= z+57 and L2 : x-21= y-44= z-67. If is the acute angle between the lines L and L3 : x- 872= y- 471= z2, then is equal to :

  1. 32 2
  2. 52 2
  3. 53 2
  4. 43 2
JEE Main 2026 (Online) 6th April Morning Shift
4

The shortest distance between the lines x-41= y-32= z-2-3 and x+22= y-64= z-5-5 is :

  1. 5 66
  2. 2 5
  3. 3 5
  4. 4 5
JEE Main 2026 (Online) 6th April Evening Shift
5

Let the image of the point P(0, -5, 0) in the line x-12= y1= z+1-2 be the point R and the image of the point Q (0, -12, 0 ) in the line x-1-1= y+94= z+11 be the point S. Then the square of the area of the parallelogram PQRS is .

JEE Main 2026 (Online) 6th April Evening Shift
6

The square of the distance of the point P(5, 6, 7) from the line x-22= y-53= z-24 is equal to:

  1. 3
  2. 5
  3. 6
  4. 8
JEE Main 2026 (Online) 5th April Morning Shift
7

The square of the distance of the point of intersection of the lines r= ( i+ j- k )+ (a i- j ), a 0 and r= (4 i- k )+ (2 i+a k ) from the origin is :

  1. 5
  2. 10
  3. 17
  4. 26
JEE Main 2026 (Online) 5th April Morning Shift
8

Let a triangle PQR be such that P and Q lie on the line x+38= y-42= z+12 and are at a distance of 6 units from R(1, 2, 3). If ( , , ) is the centroid of PQR, then + + is equal to :

  1. 4
  2. 5
  3. 6
  4. 8
JEE Main 2026 (Online) 5th April Evening Shift
9

If the distance of the point (a, 2, 5) from the image of the point (1, 2, 7) in the line x1= y-11= z-22 is 4, then the sum of all possible values of a is equal to :

  1. 11
  2. 9
  3. 6
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JEE Main 2026 (Online) 5th April Evening Shift
10

A line with direction ratios 1, -1, 2 intersects the lines x2= y3= z+13 and x+1-1= y-21= z4 at the points P and Q, respectively. If the length of the line segment PQ is , then 225 2 is equal to:

  1. 1024
  2. 1014
  3. 1104
  4. 1204
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11

The square of the distance of the point (-2, -8, 6) from the line x-11= y-12= z-1 along the line x+51= y+5-1= z2 is equal to:

  1. 3
  2. 6
  3. 8
  4. 12
JEE Main 2026 (Online) 4th April Morning Shift

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