Answer
$\dfrac{5}{3}$
Work Step by Step
The distance formula for two vectors can be calculated as:
$d=\dfrac{|p \cdot q|}{|q|}$
Now, $p \cdot q=0(2)+5(1)+0(2)=5$
and $|p \times q|=|5|=5$
Thus, $d=\dfrac{5}{ \sqrt {(2)^2+(1)^2+(2)^2}}=\dfrac{5}{ \sqrt {4+1+4}}$
or, $=\dfrac{5}{ \sqrt {9}}$
or, $=\dfrac{5}{3}$
