+33665 You can use the calculator here to find A using the tan-1 (or atan) function (press the 2nd button on the calculator to see atan).
$${\mathtt{A}} = \underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{tan}}^{\!\!\mathtt{-1}}{\left({\frac{{\mathtt{3}}}{{\sqrt{{\mathtt{5}}}}}}\right)} \Rightarrow {\mathtt{A}} = {\mathtt{53.300\: \!774\: \!799\: \!51^{\circ}}}$$
This is the result in the 1st quadrant. tan is also positive in the third quadrant so you could also add 180° to the above to get another value within the range 0° to 360°
+33665 You can use the calculator here to find A using the tan-1 (or atan) function (press the 2nd button on the calculator to see atan).
$${\mathtt{A}} = \underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{tan}}^{\!\!\mathtt{-1}}{\left({\frac{{\mathtt{3}}}{{\sqrt{{\mathtt{5}}}}}}\right)} \Rightarrow {\mathtt{A}} = {\mathtt{53.300\: \!774\: \!799\: \!51^{\circ}}}$$
This is the result in the 1st quadrant. tan is also positive in the third quadrant so you could also add 180° to the above to get another value within the range 0° to 360°
