Ответ:

  1. \(\sqrt{72}\cdot\sqrt{2}=\sqrt{144}=12\).
  2. \(\sqrt{45}\cdot\sqrt{5}=\sqrt{225}=15\).
  3. \(\sqrt{360}\cdot\sqrt{490}=\sqrt{176400}=420\).
  4. \(\sqrt{0{,}9}\cdot\sqrt{1{,}6}=\sqrt{1{,}44}=1{,}2\).
  5. \(\frac{\sqrt{242}}{\sqrt{2}}=\sqrt{121}=11\).
  6. \(-\frac{\sqrt{40}}{\sqrt{0{,}025}}=-\sqrt{1600}=-40\).

Ответ: 1) 12; 2) 15; 3) 420; 4) 1,2; 5) 11; 6) −40.