tolong dong bantuin tentang trigonometri

[tex] \cos \alpha = - \frac{4}{5} \: \frac {-> (samping)}{-> (miring)}\\ \\ \frac{\pi}{2} < \alpha < \pi \\ \frac{180}{2} < \alpha < 180 \\ 90 < \alpha < 180 \: \: \: -> kuadran \: 2 \\ kuadran \: 2 \: ( \sin \: positif) \\ \\ \sin \: \alpha = \frac{depan }{miring} \\ \sin \alpha = \frac{3}{5} [/tex]

Jadi, jawabannya D.