Our figure is a regular polygon. A polygon is regular when all angles are equal and all sides are equal. The measure of each inside angle of a regular polygon is given by the following expression
[tex]\frac{180^o\times(n-2)}{n}[/tex]Where n represents the amount of sides.
Since our polygon is a regular hexagon, we have n = 6. Using this value on the expression, we have
[tex]\frac{180^o\times(6-2)}{6}=\frac{180^o\times4}{6}=\frac{720^o}{6}=120^o[/tex]The measure of each interior angle a regular hexagon is 120º.