28. Вычислите: 1) \(\sqrt[6]{36^3}\); 2) \(\sqrt[12]{64^2}\); 3) \(\sqrt[4]{\left(\frac{1}{25}\right)^2}\); 4) \(\sqrt[8]{225^4}\).

1. \(\sqrt[6]{36^3}=36^{3/6}=36^{1/2}=6\).
2. \(\sqrt[12]{64^2}=64^{2/12}=64^{1/6}=2\).
3. \(\sqrt[4]{\left(\frac{1}{25}\right)^2}=\left(\frac{1}{25}\right)^{1/2}=\frac{1}{5}\).
4. \(\sqrt[8]{225^4}=225^{4/8}=\sqrt{225}=15\).

Ответ: 1) 6; 2) 2; 3) \(\frac{1}{5}\); 4) 15.