Question

If points $P(3,2,1),R(4,y,z),4Q(2,-1,3)$ lie on the same line, then distance of point R from origin is?

• A. $\sqrt{21}$
• B. $2\sqrt{20}$
• C. $\sqrt{42}$
• D. $\sqrt{31}$

Answer 1

Answer: (C)

$\sqrt{42}$

$PQ:\frac{x-3}{1}=\frac{y-2}{3}=\frac{z-1}{-2}$
R and PQ
$\frac{4-3}{1}=\frac{y-2}{3}=\frac{z-1}{-2}$
$R(4,5,-1)$
$\therefore OR=\sqrt{16+25+1}=\sqrt{42}$.