Answer
The orthogonal distance $D$ from the plane to the origin is
$D = \frac{5}{{\sqrt {14} }} \simeq 1.3363$
Work Step by Step
Refer to Exercise 69: the the orthogonal distance $D$ from the plane $\Pi $ with equation $ax + by + cz = d$ to the origin $O$ is equal to
$D = \frac{{\left| d \right|}}{{\sqrt {{a^2} + {b^2} + {c^2}} }}$
Using this formula, the orthogonal distance $D$ from the plane $x+2y+3z=5$ to the origin is
$D = \frac{5}{{\sqrt {{1^2} + {2^2} + {3^2}} }} = \frac{5}{{\sqrt {14} }} \simeq 1.3363$
