10. Вычислить: 1) √68 · √28; 2) √20 · √5; 3) √50 : √8; 4) √12 : √27.

1. \(\sqrt{68}\cdot\sqrt{28}=\sqrt{68\cdot28}=\sqrt{1904}=\sqrt{16\cdot119}=4\sqrt{119}\).
2. \(\sqrt{20}\cdot\sqrt{5}=\sqrt{100}=10\).
3. \(\sqrt{50}:\sqrt{8}=\sqrt{\frac{50}{8}}=\sqrt{\frac{25}{4}}=\frac{5}{2}\).
4. \(\sqrt{12}:\sqrt{27}=\sqrt{\frac{12}{27}}=\sqrt{\frac{4}{9}}=\frac{2}{3}\).

Ответ: 1) \(4\sqrt{119}\); 2) 10; 3) \(\frac{5}{2}\); 4) \(\frac{2}{3}\).