tan-1(7/12)

On the web2 calc use arc tan.  It is the same as inverse tan.

atan(7/12)

$$\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{tan}}^{\!\!\mathtt{-1}}{\left({\frac{{\mathtt{7}}}{{\mathtt{12}}}}\right)} = {\mathtt{30.256\: \!437\: \!163\: \!529^{\circ}}}$$

Anon is talking about inverse tangent.

Inverse tan of (7/12) is approximately 30.256 degrees.