364. 1) \(\dfrac{\sqrt{27}}{\sqrt{3}}\); 2) \(\dfrac{\sqrt{128}}{\sqrt{8}}\); 3) \(\dfrac{\sqrt[4]{40}}{\sqrt{10}}\); 4) \(\dfrac{\sqrt[20]{18}}{\sqrt[5]{2}}\).

1. \(\dfrac{\sqrt{27}}{\sqrt{3}}=\sqrt{\dfrac{27}{3}}=\sqrt{9}=3\).
2. \(\dfrac{\sqrt{128}}{\sqrt{8}}=\sqrt{\dfrac{128}{8}}=\sqrt{16}=4\).
3. \(\dfrac{\sqrt[4]{40}}{\sqrt{10}}=\dfrac{\sqrt[4]{40}}{\sqrt[4]{100}}=\sqrt[4]{\dfrac{40}{100}}=\sqrt[4]{\dfrac{2}{5}}\).
4. \(\dfrac{\sqrt[20]{18}}{\sqrt[5]{2}}=\dfrac{\sqrt[20]{18}}{\sqrt[20]{16}}=\sqrt[20]{\dfrac{18}{16}}=\sqrt[20]{\dfrac{9}{8}}\).

Ответ: 1) 3; 2) 4; 3) \(\sqrt[4]{\dfrac{2}{5}}\); 4) \(\sqrt[20]{\dfrac{9}{8}}\).