Ответ:

  1. \(\sqrt{45}\cdot\sqrt{5}=\sqrt{225}=15\).

  2. \(\sqrt{160}\cdot\sqrt{250}=\sqrt{40000}=200\).

  3. \(\frac{\sqrt{108}}{\sqrt{3}}=\sqrt{\frac{108}{3}}=\sqrt{36}=6\).

  4. \(\frac{\sqrt{90}}{\sqrt{0.016}}=\sqrt{\frac{90}{0.016}}=\sqrt{5625}=75\).

Ответ: 1) 15; 2) 200; 3) 6; 4) 75.