Решение:

1. $$\sqrt{\frac{81}{100}} = \frac{\sqrt{81}}{\sqrt{100}} = \frac{9}{10} = 0.9$$
2. $$\sqrt{\frac{49}{256}} = \frac{\sqrt{49}}{\sqrt{256}} = \frac{7}{16}$$

Ответ:

• $$\sqrt{\frac{81}{100}} = 0.9$$
• $$\sqrt{\frac{49}{256}} = \frac{7}{16}$$