Find the foot of perpendicular from the point (2, 3, 4) to the line Also, find the perpendicular distance from the given point to the line.


Given: - Point P(2, 3, 4) and the equation of the line


Let, PQ be the perpendicular drawn from P to given line whose endpoint/ foot is Q point.


Thus to find Distance PQ we have to first find coordinates of Q



x = 4 – 2λ, y = 6λ, z = 1 – 3λ


Therefore, coordinates of Q( – 2λ + 4, 6λ, – 3λ + 1)


Now as we know (TIP) ‘if two points A(x1,y1,z1) and B(x2,y2,z2) on a line, then its direction ratios are proportional to (x2 – x1,y2 – y1,z2 – z1)’


Hence


Direction ratio of PQ is


= ( – 2λ + 4 – 2), (6λ – 3), ( – 3λ + 1 – 4)


= ( – 2λ + 2), (6λ – 3), ( – 3λ – 3)


and by comparing with given line equation, direction ratios of the given line are


(hint: denominator terms of line equation)


= ( – 2,6, – 3)


Since PQ is perpendicular to given line, therefore by “condition of perpendicularity.”


a1a2 + b1b2 + c1c2 = 0 ; where a terms and b terms are direction ratio of lines which are perpendicular to each other.


– 2( – 2λ + 2) + (6)(6λ – 3) – 3( – 3λ – 3) = 0


4λ – 4 + 36λ – 18 + 9λ + 9 = 0


49λ – 13 = 0



Therefore coordinates of Q


i.e. Foot of perpendicular


By putting the value of λ in Q coordinate equation, we get




Now,


Distance between PQ


Tip: - Distance between two points A(x1,y1,z1) and B(x2,y2,z2) is given by








units


5
1