Answer
$\sqrt 2$
Work Step by Step
The distance formula for two vectors $p$ and $q$ is defined as:
$d=\dfrac{|p \cdot q|}{|p|}$
Thus, we have $p \cdot q=-2(1)+(0)(-1)+6(0)=-2$
and $|p \cdot q|=|-2|=2$
Now, $d=\dfrac{2}{ \sqrt {(1)^2+(-1)^2+(0)^2}}=\dfrac{2}{\sqrt {2}}=\sqrt 2$
