To determine the number of sides of a regular polygon given that its interior angle measures \(108^\circ\), we can use the formula for the interior angle of a regular polygon:
\[
\text{Interior angle} = \frac{(n-2) \times 180^\circ}{n}
\]
where \(n\) is the number of sides of the polygon. We are given that the interior angle is \(108^\circ\), so we set up the equation:
\[
108 = \frac{(n-2) \times 180}{n}
\]
To solve for \(n\), we first multiply both sides by \(n\) to eliminate the fraction:
\[
108n = (n-2) \times 180
\]
Expanding the right side, we have:
\[
108n = 180n - 360
\]
Next, we rearrange the equation to isolate terms involving \(n\) on one side:
\[
180n - 108n = 360
\]
Simplifying, we get:
\[
72n = 360
\]
Now, divide both sides by 72 to solve for \(n\):
\[
n = \frac{360}{72} = 5
\]
Therefore, the polygon has 5 sides.
In summary, the polygon is a regular pentagon, as it has 5 sides.