1) Вычислить: 1) \(0.4\sqrt{6400}\); 2) \(100\sqrt{0.16}-\frac{1}{26}\sqrt{169}\); 3) \(\frac{2}{9}\sqrt{5\frac{1}{16}}\); 4) \(\sqrt{784}-10\sqrt{2.56}\).

1. \(0.4\sqrt{6400}=0.4\cdot80=32\).
2. \(100\sqrt{0.16}-\frac{1}{26}\sqrt{169}=100\cdot0.4-\frac{13}{26}=40-0.5=39.5\).
3. \(\frac{2}{9}\sqrt{5\frac{1}{16}}=\frac{2}{9}\sqrt{\frac{81}{16}}=\frac{2}{9}\cdot\frac{9}{4}=\frac12\).
4. \(\sqrt{784}-10\sqrt{2.56}=28-10\cdot1.6=12\).

Ответ: 1) 32; 2) 39.5; 3) \(\frac12\); 4) 12.