10. Вычислить: 1) \(\sqrt{63}\cdot\sqrt{28}\); 2) \(\sqrt{20}\cdot\sqrt5\); 3) \(\sqrt{50}:\sqrt8\); 4) \(\sqrt{12}:\sqrt{27}\).

1. \(\sqrt{63}\cdot\sqrt{28}=\sqrt{1764}=42\).
2. \(\sqrt{20}\cdot\sqrt5=\sqrt{100}=10\).
3. \(\sqrt{50}:\sqrt8=\sqrt{\frac{50}{8}}=\sqrt{\frac{25}{4}}=\frac52\).
4. \(\sqrt{12}:\sqrt{27}=\sqrt{\frac{12}{27}}=\sqrt{\frac49}=\frac23\).

Ответ: 1) 42; 2) 10; 3) \(\frac52\); 4) \(\frac23\).