The sum of the interior angles of a polygon is given by:
[tex]\text{Sum}=(n-2)\times180[/tex]Where n is the number of sides of the polygon.
A regular 30-gon has 30 sides, then the sum is:
[tex]\begin{gathered} \text{Sum}=(30-2)\times180 \\ \text{Sum}=28\times180 \\ \text{Sum}=5040 \end{gathered}[/tex]Now, we have to divide the total sum by the number of angles, then:
[tex]\frac{5040}{30}=168[/tex]Answer: One interior angle of a regular 30-gon measures 168°.