In the following cases, find the coordinates of the foot of the perpendicular drawn from the origin.

x + y + z = 1

Let the coordinate of the foot of P from the origin to the given plane be P(x,y,z).

0x – 5y + 0z = 8


Direction ratio (0,-5,0)




= 5



This is the form of


lx + my + nz = d ( d = Distance of the normal from the origin.)



Coordinate of the foot (ld,md,nd)


4