Answer
$|C-27.5|\le0.25$
Work Step by Step
Half-way between the given values, $
27.25\text{ and } 27.75
,$ is
\begin{array}{l}\require{cancel}
\dfrac{27.25+27.75}{2}
\\\\=
\dfrac{55}{2}
\\\\=
27.5
.\end{array}
The distance from $
27.5
$ to $27.25$ and $27.75$ is $
0.25
.$
Since $|x|\lt c$ implies $-c\lt x\lt c$ (or $|x|\le c$ implies $-c\le x\le c$), then the given inequality, $
27.25\le C\le27.75
,$ is equivalent to
\begin{array}{l}\require{cancel}
|C-27.5|\le0.25
.\end{array}
