For this problem we want to estimate:
[tex]\sqrt{388}[/tex]We need to take in count that this number is not a perfect square. And we can use the following definition:
[tex]\sqrt{x}=\sqrt{nearestp\operatorname{erf}ectsquare}\text{ + }\frac{x-p\operatorname{erf}ectsquare}{2\sqrt{p\operatorname{erf}ectsquare}}[/tex]The nearest perfect square to 388 is 361 because:
[tex]\sqrt{361}=\text{ }\sqrt{19\cdot19}=19[/tex]And replacing we have:
[tex]\sqrt{388}=\sqrt{361}+\frac{388-361}{2\sqrt{361}}=19+\frac{27}{2\cdot19}=19+\frac{27}{38}\text{ }[/tex][tex]A=361,B=19,C=400,D=20,E=19,F=20[/tex]