#### Answer

$d=6$

#### Work Step by Step

$\bf{\text{Solution Outline:}}$
To find the common difference of the given arithmetic sequence, $
4, 10, 16, 22, ...
,$ subtract a term by its previous term.
$\bf{\text{Solution Details:}}$
Since the common difference of an arithmetic sequence is the difference between a term and its previous term, then with $a_2=
10
$ and $a_1=
4
$, the common difference, $d$, is
\begin{array}{l}\require{cancel}
d=10-4
\\\\
d=6
.\end{array}