Expand the following: \begin{align} tan(α)= \frac{sin(α)}{cos(α)} =&\cssId{Step1}{tan(α)=\frac{y}{l/2}}\\[3px] &\cssId{Step2}{α=arctan\frac{y*2}{l}}\\[3px] \end{align}

- Firstly, we use tangent because we have the opposite and the adjacent side of the imaginary trinagle.
- Secondly, we change the sides to the distances that we know.
- Finally, you pass the tangent to the other side of the equation so you got all the data to know alpha.