а) $$ \sqrt{\frac{1}{36}} = \frac{\sqrt{1}}{\sqrt{36}} = \frac{1}{6} $$.
Ответ: $$\frac{1}{6}$$
б) $$ \sqrt{\frac{169}{144}} = \frac{\sqrt{169}}{\sqrt{144}} = \frac{13}{12} $$.
Ответ: $$\frac{13}{12}$$