$\sqrt{9\ast 25}=\sqrt{9}\ast \sqrt{25}=3\ast 5=15$

$\sqrt{16\ast 2500}=\sqrt{16}\ast \sqrt{2500}=4\ast 50=200$

$\sqrt{0,64\ast 36}=\sqrt{0,64}\ast \sqrt{36}=0,8\ast 6=4,8$

$\sqrt{400\ast 1,44}=\sqrt{400}\ast \sqrt{1,44}=20\ast 1,2=24$

$\sqrt{0,09\ast 0,04}=\sqrt{0,09}\ast \sqrt{0,04}=0,3\ast 0,2=0,06$

$\sqrt{6,25\ast 0,16}=\sqrt{6,25}\ast \sqrt{0,16}=2,5\ast 0,4=1$

$\sqrt{6^2\ast 3^4}=\sqrt{6^2}\ast \sqrt{3^4}=\sqrt{6^2}\ast \sqrt{(3^2{)}^2}=|6|\ast |3^2|=6\ast 9=54$

$\sqrt{7^2\ast 2^8}=\sqrt{7^2}\ast \sqrt{(2^4{)}^2}=|7|\ast |2^4|=7\ast 16=112$

$\sqrt{25\ast 64\ast 0,36}=\sqrt{25}\ast \sqrt{64}\ast \sqrt{0,36}=5\ast 8\ast 0,6=40\ast 0,6=24$

$\sqrt{0,01\ast 0,81\ast 2500}=\sqrt{0,01}\ast \sqrt{0,81}\ast \sqrt{2500}=0,1\ast 0,9\ast 50=0,9\ast 5=4,5$

$\sqrt{\frac{81}{100}}=\frac{\sqrt{81}}{\sqrt{100}}=\frac{9}{10}=0,9$

$\sqrt{\frac{49}{256}}=\frac{\sqrt{49}}{\sqrt{256}}=\frac{7}{16}$

$\sqrt{3\frac{13}{36}}=\sqrt{\frac{121}{36}}=\frac{\sqrt{121}}{\sqrt{36}}=\frac{11}{6}=1\frac{5}{6}$

$\sqrt{3\frac{1}{16}\ast 2\frac{14}{25}}=\sqrt{\frac{49}{16}\ast \frac{64}{25}}=\sqrt{\frac{49}{16}}\ast \sqrt{\frac{64}{25}}=\frac{\sqrt{49}}{\sqrt{16}}\ast \frac{\sqrt{64}}{\sqrt{25}}=\frac{7}{4}\ast \frac{8}{5}=\frac{7}{1}\ast \frac{2}{5}=\frac{14}{5}=2\frac{4}{5}$

$\sqrt{\frac{169}{36\ast 81}}=\frac{\sqrt{169}}{\sqrt{36}\ast \sqrt{81}}=\frac{\sqrt{169}}{\sqrt{36\ast 81}}=\frac{13}{6\ast 9}=\frac{13}{54}$

$\sqrt{\frac{121\ast 256}{25\ast 100}}=\frac{\sqrt{121\ast 256}}{\sqrt{25\ast 100}}=\frac{\sqrt{121}\ast \sqrt{256}}{\sqrt{25}\ast \sqrt{100}}=\frac{11\ast 16}{5\ast 10}=\frac{11\ast 8}{5\ast 5}=\frac{88}{25}=3\frac{13}{25}$