III-в. Вычислить: 1) \(0,5\cdot\sqrt{36}\); 2) \(\sqrt{10}\cdot\sqrt{40}\); 3) \(\dfrac{\sqrt{8}}{\sqrt{50}}\); 4) \(2,5-2\sqrt{0,3}\cdot\sqrt{2,7}\).

1. \(0,5\cdot\sqrt{36}=0,5\cdot6=3\).
2. \(\sqrt{10}\cdot\sqrt{40}=\sqrt{400}=20\).
3. \(\dfrac{\sqrt{8}}{\sqrt{50}}=\sqrt{\dfrac{8}{50}}=\sqrt{\dfrac{4}{25}}=\dfrac{2}{5}\).
4. \(2,5-2\sqrt{0,3}\cdot\sqrt{2,7}=2,5-2\sqrt{0,81}=2,5-2\cdot0,9=0,7\).

Ответ: 1) 3; 2) 20; 3) \(\dfrac{2}{5}\); 4) 0,7.