Find the coordinates of the foot of the perpendicular drawn from the point (1, 2, 3) to the line
Also, find the length of the perpendicular from the given point to the line.
Given: Equation of line is 
To find: coordinates of foot of the perpendicular from (1, 2, 3) to the line. And find the length of the perpendicular.
Formula Used:
1. Equation of a line is
Cartesian form: ![]()
where
is a point on the line and b1 : b2 : b3 is the direction ratios of the line.
2. Distance between two points (x1, y1, z1) and (x2, y2, z2) is
![]()
Explanation:
Let
![]()
So the foot of the perpendicular is (3λ + 6, 2λ + 7, -2λ + 7)
Direction ratio of the line is 3 : 2 : -2
Direction ratio of the perpendicular is
⇒ (3λ + 6 - 1) : (2λ + 7 - 2) : (-2λ + 7 - 3)
⇒ (3λ + 5) : (2λ + 5) : (-2λ + 4)
Since this is perpendicular to the line,
3(3λ + 5) + 2(2λ + 5) – 2(-2λ + 4) = 0
⇒ 9λ + 15 + 4λ + 10 + 4λ – 8 = 0
⇒ 17λ = -17
⇒ λ = -1
So the foot of the perpendicular is (3, 5, 9)
Distance ![]()
![]()
= 7 units
Therefore, the foot of the perpendicular is (3, 5, 9) and length of perpendicular is 7 units.
Couldn't generate an explanation.
Generated by AI. May contain inaccuracies — always verify with your textbook.




