[tex] \to \rm \sin(30) = \dfrac{AC }{AB}[/tex]
[tex] \\ \\ [/tex]
[tex] \to \rm \sin(30) = \dfrac{AC }{40}[/tex]
[tex] \\ \\ [/tex]
[tex] \to \rm \dfrac{1}{2} = \dfrac{AC }{40 \degree}[/tex]
[tex] \\ \\ [/tex]
[tex] \to \rm \dfrac{40}{2} =AC [/tex]
[tex] \\ \\ [/tex]
[tex] \to \rm \: AC = 20 m[/tex]
