Question 587142
If the coordinates of the point where the terminal side intersects the unit circle are ({{{-5/13}}},{{{12/13}}}), the tangent can be found as
{{{tan(theta)=(12/13)/((-5/13))=-12/5=-2.4}}}
The measure of that angle, by the way, is approximately {{{112.7^o}}}.
If the terminal side were the reflection on the y-axis, you would have the reference angle, measuring
{{{67.4^o=180^o-112.7^o}}}.
Then you would see {{{tan(theta)}}} as a ratio of sides in a right triangle
{{{tan(theta)=opposite_side/adjacent_side)}}}