$\text{a)}$  

$\sqrt{1}=1$  

$\sqrt{\frac{25}{49}}=\frac{5}{7}$

$\sqrt{2\frac{1}{4}}=\sqrt{\frac{9}{4}}=\frac{3}{2}=1,5$

$\sqrt{0,01}=0,1$

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$\text{b)}$

$\sqrt{289}=17$

$\sqrt{\frac{36}{121}}=\frac{6}{11}$

$\sqrt{4\frac{21}{25}}=\sqrt{\frac{121}{25}}=\frac{11}{5}=2\frac{1}{5}$

$\sqrt{2,89}=1,7$