Answer:
A. 18
Step-by-step explanation:
Sum of the measures of all the angles of a quadrilateral is 360°
Therefore,
[tex]2m \degree + 8m \degree + 6m \degree + 4m \degree = 360 \degree \\ 20m \degree = 360 \degree \\ 20m = 360 \\ m = \frac{360}{20} \\ m = 18[/tex]
