Let's draw a diagram of the situation:
The value of thetramp (Slope) is given by:
[tex]slope=\frac{rise}{run}[/tex]
Since the slope has to be:
[tex]slope=1:12=\frac{1}{12}[/tex]
And:
[tex]rise=4[/tex][tex]\begin{gathered} \frac{1}{12}=\frac{4}{run} \\ run=48 \end{gathered}[/tex]
So, the other dimension is 48ft. And the angle of elevation is given by:
[tex]\begin{gathered} \theta=tan^{-1}(\frac{4}{48}) \\ \theta\approx4.76^{\circ} \end{gathered}[/tex]
