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Question:

The length of the perpendicular form the point (2, -1, 4) on the straight line x+3/10 = y-2/-7 = z/1 is:

greater than 3 but less than 4

less than 2

greater than 4

greater than 2 but less than 3

Solution:

Correct option is B. greater than 3 but less than 4=(2, -32, 12)Now,MP→ (10i^ -7j^+k^)=0 λ=12 ∴Length of perpendicular(=PM)=√0+14+494=√504=√252=5√2, which is greater than 3 but less than 4