Question

If the $zx$-plane divides the line segment joining $(1,-1,5)$ and $(2,3,4)$ in the ratio $p:1$, then $p+1=$

• A. $\frac{1}{3}$
• B. $1:3$
• C. $\frac{3}{4}$
• D. $\frac{4}{3}$

Answer 1

Answer: (D)

$\frac{4}{3}$

Given points are $(1,-1,5)$ and $(2,3,4)$

since ZX-plane divides the line segment in the ratio $p:1,$y-coordinate will be $0$

the y-coordinate of the point dividing the line segment will be $\frac{3p-1}{p+1}=0$

$p=\frac{1}{3}$

$p+1=\frac{1}{3}+1=\frac{4}{3}$