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1. ⇒  (MHT CET 2023 11th May Evening Shift )

If the line x 1 2 = y + 1 3 = z 2 4 meets the plane x + 2 y + 3 z = 15 at the point P , then the distance of P from the origin is

A. 7 2 units

B. 9 2 units

C. 5 2 units

D. 2 5 units

Correct answer option is (B)

Let x 1 2 = y + 1 3 = z 2 4 = k (say)

Let P be the any point on the above line.

P ( 2 k + 1 , 3 k 1 , 4 k + 2 )

The point P lies on the plane

2 k + 1 + 2 ( 3 k 1 ) + 3 ( 4 k + 2 ) = 15 2 k + 1 + 6 k 2 + 12 k + 6 = 15 20 k = 10 k = 1 2 P ( 2 , 1 2 , 4 )

Distance of P from origin is

2 2 + ( 1 2 ) 2 + 4 2 = 81 4 = 9 2

2. ⇒  (MHT CET 2023 10th May Evening Shift )

The perpendicular distance of the origin from the plane x 3 y + 4 z 6 = 0 is

A. 6

B. 6 26

C. 1 26

D. 3 26

Correct answer option is (B)

Length of perpendicular from point O ( 0 , 0 , 0 ) to plane x 3 y + 4 z 6 = 0 is given by

d = | 0 ( 1 ) + 0 ( 3 ) + 0 ( 4 ) 6 ( 1 ) 2 + ( 3 ) 2 + ( 4 ) 2 | = | 6 1 + 9 + 16 | = 6 26