5) \( \sqrt{\frac{25}{49}} \)

\( 25 = 5^2, \; 49 = 7^2 \)\( \Rightarrow \sqrt{\frac{25}{49}} = \frac{\sqrt{25}}{\sqrt{49}} = \frac{5}{7} \). Ответ: \( \frac{5}{7} \).