Three Dimensional Geometry Question 326
Question: If x co-ordinates of a point P of line joining the points Q (2, 2, 1) and R (5, 2, - 2) is 4, then the z-coordinates of P is
Options:
A) -2
B) -1
C) 1
D) 2
Show Answer
Answer:
Correct Answer: B
Solution:
[b] Suppose P divides QR in ratio $ \lambda :1 $ . Then, co-ordinates of P are $ ( \frac{5\lambda +2}{\lambda +1},\frac{\lambda +2}{\lambda +1},\frac{-2\lambda +1}{\lambda +1} ) $ . It is given that the x-coordinate of P is 4. i.e., $ \frac{5\lambda +2}{\lambda +1}=4\Rightarrow \lambda =2 $ So, z-coordinate of P is $ \frac{-2\lambda +1}{\lambda +1}=\frac{-4+1}{2+1}=-1 $ .
BETA
