\[\sqrt{\frac{9}{16}} + \sqrt{\frac{25}{36}} = \frac{\sqrt{9}}{\sqrt{16}} + \frac{\sqrt{25}}{\sqrt{36}} = \frac{3}{4} + \frac{5}{6}\]
\[\frac{3}{4} + \frac{5}{6} = \frac{3 \cdot 3}{4 \cdot 3} + \frac{5 \cdot 2}{6 \cdot 2} = \frac{9}{12} + \frac{10}{12} = \frac{19}{12}\]
\[\sqrt{\frac{13}{36}} = \frac{\sqrt{13}}{\sqrt{36}} = \frac{\sqrt{13}}{6}\]
\[\sqrt{\frac{25}{6}} \cdot \sqrt{\frac{3}{4}} \cdot \sqrt{\frac{4}{294}} = \frac{\sqrt{25}}{\sqrt{6}} \cdot \frac{\sqrt{3}}{\sqrt{4}} \cdot \frac{\sqrt{4}}{\sqrt{294}} = \frac{5}{\sqrt{6}} \cdot \frac{\sqrt{3}}{2} \cdot \frac{2}{\sqrt{294}}\]
\[\frac{5}{\sqrt{6}} \cdot \frac{\sqrt{3}}{2} \cdot \frac{2}{\sqrt{294}} = \frac{5 \cdot \sqrt{3} \cdot 2}{\sqrt{6} \cdot 2 \cdot \sqrt{294}} = \frac{5 \sqrt{3}}{ \sqrt{6 \cdot 294}} = \frac{5 \sqrt{3}}{2 \sqrt{3 \cdot 294}} = \frac{5 \sqrt{3}}{2 \sqrt{882}}\]
\[\frac{5 \sqrt{3}}{2 \sqrt{882}} = \frac{5 \sqrt{3}}{2 \sqrt{2 \cdot 3^2 \cdot 7^2}} = \frac{5 \sqrt{3}}{2 \cdot 3 \cdot 7 \sqrt{2}} = \frac{5 \sqrt{3}}{42 \sqrt{2}} = \frac{5 \sqrt{3} \sqrt{2}}{42 \sqrt{2} \sqrt{2}} = \frac{5 \sqrt{6}}{84}\]
\[\sqrt{113^2 - 112^2} = \sqrt{(113 - 112)(113 + 112)} = \sqrt{1 \cdot 225} = \sqrt{225} = 15\]
Ответ: 1) \(\frac{19}{12}\); 2) \(\frac{\sqrt{13}}{6}\); 3) \(\frac{5 \sqrt{6}}{84}\); 4) 15