To find the length of one side of a cube with a given volume, you can use the formula for the volume of a cube:
\[ V = s^3 \]
where \( V \) is the volume and \( s \) is the length of one side.
Given that the volume \( V = 27 \) cubic units, you can set up the equation:
\[ s^3 = 27 \]
To find \( s \), take the cube root of both sides:
\[ s = \sqrt[3]{27} \]
Calculating the cube root:
\[ s = 3 \]
Thus, the length of one side of the cube is \( 3 \) units.