Pentru rezolvarea exercitiului se va folosi teorema sinusului.
[tex]\frac{a}{sin A}=\frac{b}{sin B}=\frac{c}{sin C}[/tex]
Avem: a=BC=2 ; b=AC; c= AB=4; sin C =sin 60
[tex]\frac{2}{sin \ A}=\frac{AC}{sin \ B}=\frac{4}{sin \ 60^o} \\\\ \frac{2}{sin \ A}=\frac{4}{\frac{\sqrt{3}}{2}} \\\\ sin \ A= \not2* \frac{\sqrt{3}}{\not2} * \frac{1}{4} \\\\ \boxed{sin \ A \to \frac{\sqrt{3}}{4}}[/tex]
