[tex]\sqrt{\frac{81}{100} . \frac{4}{9}[/tex]

[tex]\sqrt{\frac{9}{25}.\frac{1}{4}.\frac{49}{64}[/tex]

[tex]\sqrt{1 - \frac{3}{4}[/tex]

[tex]\sqrt\frac{1}{16} . ^{3} \sqrt{2} . ^{3} \sqrt{-27}[/tex]