we must use trigonometric ratios
we will use Tan
[tex]\tan \alpha=\frac{\text{opposite }}{\text{adjacent}}[/tex]
so replacing
[tex]\tan (3)=\frac{x}{160}[/tex]
and solve x
[tex]\begin{gathered} x=160\times\tan (3) \\ \\ x=8.39 \end{gathered}[/tex]
the dustance betweem the ship and lighthouse is 8.4ft
