a) `\sqrt{12.30.40}` = `\sqrt{12.3.10.4.10}` =`\sqrt{36.4.100}`=`\sqrt{36}`.`\sqrt{4}`.`\sqrt{100}`= `6.2.10`=`120`
b) `\sqrt{27/2a}`.`\sqrt{{2a}/3}`= `\sqrt{27/2a . {2a}/3}` = `\sqrt{9}`=`3`
c) `\sqrt{49.64}` =`\sqrt{49}`.`\sqrt{64}`=`7.8`=`56`
d) `\sqrt{0,4.360}`=`\sqrt{0,4.10.36}`=`\sqrt{4.36}`=`\sqrt{4}`.`\sqrt{36}`=`2.6`=`12`