Ответ:

  1. а) \(\frac{\sqrt2}{\sqrt{50}}=\sqrt{\frac{2}{50}}=\sqrt{\frac1{25}}=\frac15\).
  2. б) \(\frac{\sqrt{75}}{\sqrt{192}}=\sqrt{\frac{75}{192}}=\sqrt{\frac{25}{64}}=\frac58\).
  3. в) \(\sqrt{63}\cdot\sqrt7=\sqrt{441}=21\).
  4. г) \(\sqrt{10}\cdot\sqrt{90}=\sqrt{900}=30\).
  5. \(\sqrt{81\cdot100\cdot4}=9\cdot10\cdot2=180\).
  6. \(\sqrt{0{,}01\cdot81\cdot0{,}25}=\sqrt{0{,}2025}=0{,}45\).
  7. \(5\frac{1}{16}=\frac{81}{16}\), \(2\frac{34}{81}=\frac{196}{81}\). Поэтому \(\sqrt{\frac{81}{16}\cdot\frac{196}{81}}=\sqrt{\frac{49}{4}}=\frac72=3{,}5\).