9.
`a)`
`\sqrt{0,09:1,44}`
`=\sqrt{0,09}:\sqrt{1,44}`
`=3/10:6/5`
`=1/4`
$\\$
`b)`
`\sqrt{36:225/256}`
`=\sqrt{36}:\sqrt{225/256}`
`=6:15/16`
`=32/5`
$\\$
`c)`
`\sqrt{9/16}`
`=(\sqrt{9})/(\sqrt{16})`
`=3/4`
`d)`
`\sqrt{36/25}`
`=(\sqrt{36})/(\sqrt{25})`
`=6/5`
$\\$
10.
`a)`
`\sqrt{(27^2-9^2)/50}`
`=\sqrt{((27-9)(27+9))/50}`
`=\sqrt{(18.36)/50}`
`=\sqrt{648/50}`
`=(\sqrt{648})/(\sqrt{50})`
`=(18\sqrt{2})/(5\sqrt{2})`
`=18/5`
$\\$
`b)`
`\sqrt{(143^2-53^2)/(173^2-83^2)}`
`=\sqrt{((143-53)(143+53))/((173-83)(173+83))}`
`=\sqrt{(90.196)/(90.256)}`
`=\sqrt{196/256}`
`=(\sqrt{196})/(\sqrt{256})`
`=14/16=7/8`
