To find the measure of one interior angle of a regular hexagon, you 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. For a hexagon, \( n = 6 \).
Plugging in the value:
\[ \text{Interior angle} = \frac{(6 - 2) \times 180^\circ}{6} = \frac{4 \times 180^\circ}{6} = \frac{720^\circ}{6} = 120^\circ \]
Therefore, the measure of one interior angle of a regular hexagon is \( 120^\circ \).