Question
Mathematics Question on Three Dimensional Geometry
If the distance of the point P(1,−2,1) from the plane x+2y−2z=a, where a>0, is 5, then the foot of the perpendicular form P to the plane is
A
(38,34,−37)
B
(34,34,31)
C
(31,32,310)
D
(32,31,25)
Answer
(38,34,−37)
Explanation
Solution
Distance of point P from plane = 5
\therefore \hspace15mm 5= \bigg|\frac{1-4-2-\alpha}{3}\bigg|
\Rightarrow \hspace15mm \alpha =0
Foot of perpendicular
\hspace30mm \frac{x-1}{1} = \frac{y+2}{2} = \frac{z-1}{-2}= \frac{5}{3}
\Rightarrow \hspace30mm x=\frac{8}{3}, y = \frac{4}{3},z = - \frac{7}{3}
Thus, the foot of the perpendicular is A(38,34,−37).