Simply take the arc tangent (or inverse tangent) of 3.5 . You are left with
$$\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{tan}}^{\!\!\mathtt{-1}}{\left({\mathtt{3.5}}\right)} = {\mathtt{74.054\: \!604\: \!099\: \!077^{\circ}}}$$
From this, we then know that tan (X) = 74.054604099077
Simply take the arc tangent (or inverse tangent) of 3.5 . You are left with
$$\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{tan}}^{\!\!\mathtt{-1}}{\left({\mathtt{3.5}}\right)} = {\mathtt{74.054\: \!604\: \!099\: \!077^{\circ}}}$$
From this, we then know that tan (X) = 74.054604099077
