№4. 1) \(\sqrt{75\cdot27}\); 2) \(\sqrt{72\cdot200}\); 3) \(\sqrt{1,6\cdot14,4}\); 4) \(\sqrt{1690\cdot6,4}\).

1. \(\sqrt{75\cdot27}=\sqrt{2025}=45\).
2. \(\sqrt{72\cdot200}=\sqrt{14400}=120\).
3. \(\sqrt{1,6\cdot14,4}=\sqrt{23,04}=4,8\).
4. \(\sqrt{1690\cdot6,4}=\sqrt{10816}=104\).

Ответ: 1) 45; 2) 120; 3) 4,8; 4) 104.