Question

The position vector of point $A$ is $(4,2,-3)$. If $p_1$ is perpendicular distance of $A$ from $XY-plane$ and $p_2$ is perpendicular distance from Y-axis, then $p_1+p_2=$ _______.

• A. $8$
• B. $3$
• C. $2$
• D. $7$

Answer 1

The correct option is A $8$

$P_1$ is perpendicular distance of A from XY-plane

So, $x_1=0,y_1=0,z_{=}-3$

$\therefore p_1=\sqrt{(-3{)}^2}=3$

$p_2$ is perpendicular distance from Y-axis

So, $x_1=4,y_1=0,z_1=-3$

$p_2=\sqrt{x_1^2+y_1^2}$

$\therefore p_2=\sqrt{4^2+(-3^2)}=5$

$p_1+p_2=5+3=8$.