Fill in the blanks to make the following statement true: $\sqrt{49} = \ldots \ldots$

For each question,select the proper option from four options given,to make the statement true: $0.3\overline{6}=$

Write the following in decimal form and state what kind of decimal expansion each has:
$\frac{121}{400}$

Find the value of the following expression correct to three decimal places,taking $\sqrt{2} = 1.414$,$\sqrt{3} = 1.732$,and $\sqrt{5} = 2.236$:
$\frac{\sqrt{10} - \sqrt{5}}{2}$

Classify the following numbers as rational or irrational with justification:
$(i)$ $\sqrt{196}$
$(ii)$ $3\sqrt{18}$

Find four rational numbers between $\frac{2}{9}$ and $\frac{2}{7}$.