#### Answer

$a=52$

#### Work Step by Step

$\bf{\text{Solution Outline:}}$
To solve the given equation, $
\dfrac{a}{4}=13
,$ use the multiplication principle by multiplying both sides by $4.$ Then do checking of the solution.
$\bf{\text{Solution Details:}}$
Multiplying both sides by $4,$ the given equation is equivalent to
\begin{array}{l}\require{cancel}
\dfrac{a}{4}=13
\\\\
4\left( \dfrac{a}{4} \right)=4(13)
\\\\
a=52
.\end{array}
Substituting the solved value of the variable in the given equation results to
\begin{array}{l}\require{cancel}
\dfrac{a}{4}=13
\\\\
\dfrac{52}{4}=13
\\\\
13=13
\text{ (TRUE)}
.\end{array}
Hence, the solution is $
a=52
.$