8. \(\frac{(3\sqrt{5})^2}{30}\)

\[\frac{(3\sqrt{5})^2}{30}=\frac{3^2\cdot(\sqrt{5})^2}{30}=\frac{9\cdot5}{30}=\frac{45}{30}=\frac{3}{2}.\]

Ответ: \(\frac{3}{2}\).