`\sqrt{\frac{9}{25}}`
`=\frac{\sqrt{9}}{\sqrt{25}}`
`=\frac{\sqrt{3^2}}{\sqrt{5^2}}`
`=\frac{|3|}{|5|}`
`=3/5`
`\sqrt{\frac{0,04}{121}}`
`=\frac{\sqrt{0,04}}{\sqrt{121}}`
`=\frac{\sqrt{0,2^2}}{\sqrt{11^2}}`
`=\frac{|0,2|}{|11|}`
`=\frac{0,2}{11}`
`\sqrt{49/100}`
`=\frac{\sqrt{49}}{\sqrt{100}}`
`=\frac{\sqrt{7^2}}{\sqrt{10^2}}`
`=\frac{|7|}{|10|}`
`=7/10`