[tex]\it \ a)\ \sqrt{2,5\cdot10^5} =\sqrt{2,5\cdot10\cdot10^4} =\sqrt{25\cdot(10^2)^2} =
\\\;\\
=\sqrt{5^2\cdot100^2} =5\cdot100=500[/tex]
[tex]\it\ b)\ \sqrt{4,9\cdot10^{-3}} =\sqrt{\dfrac{4,9}{10^3}} = \sqrt{\dfrac{4,9\cdot10}{10^3\cdot10}} = \sqrt{\dfrac{49}{10^4}} =
\\\;\\ \\\;\\
=\sqrt{\dfrac{49}{(10^2)^2}} = \sqrt{\dfrac{7^2}{100^2}} = \dfrac{7}{100} =0,07[/tex]
[tex]\it c) \ \sqrt{1,6\cdot10^7} =\sqrt{1,6\cdot10\cdot10^6} =\sqrt{16\cdot(10^3)^2}=
\\\;\\
=\sqrt{4^2\cdot1000^2} =4\cdot1000= 4000[/tex]
