pada segitiga abc , panjang sisi bc adalah

[tex]gunakan\ aturan\ sinus.\\ \\ cari\ dulu\ sudut\ yang\ depan\ sisi\ BC\ (\ \textless \ a)\\ \\ \ \textless \ a+75+60=180\\ \ \textless \ a=180-135\\ \ \textless \ a=45\ derajat.\\ \\ \frac {Sin\ \textless \ a}{BC}=\frac {Sin\ \textless \ b}{AC}\\ \frac {Sin45}{BC}=\frac {Sin60}{4\sqrt{3}}\\ \\ BC=\frac {Sin45.4\sqrt{3}}{Sin60}\\ BC=\frac {1}{2}\sqrt{2}.\frac {4\sqrt{3}}{\frac {1}{2}\sqrt{3}}\\ \\ BC=4\sqrt{2}.(A)[/tex]