Answer: [tex]314.28^{\circ}[/tex]
Explanation:
Given
X component of the vector is [tex]A_x=3.9[/tex]
Y component of the vector is [tex]A_y=-4[/tex]
From the figure, we can write
[tex]\Rightarrow \tan x=\dfrac{4}{3.9}\\\\\Rightarrow x=45.72^{\circ}[/tex]
Thus, the angle measured counterclockwise from the x-axis to vector A is
[tex]360^{\circ}-45.72^{\circ}=314.28^{\circ}[/tex]