For each question,select the proper option from four options given,to make the statement true: $\sqrt{5} + \sqrt{5}$ is a / an $\ldots \ldots \ldots$ number.

Find the value of the following expression correct to three decimal places,rationalizing the denominator if needed. Take $\sqrt{2} = 1.414$,$\sqrt{3} = 1.732$,and $\sqrt{5} = 2.236$.
$\frac{\sqrt{2}}{2+\sqrt{2}}$

If $(\frac{2}{5})^{5} \times (\frac{25}{4})^{3} = (\frac{5}{2})^{3x-2}$,then find $x$.

Find the value of $a$ in the following:
$\frac{6}{3 \sqrt{2}-2 \sqrt{3}}=3 \sqrt{2}-a \sqrt{3}$

$\sqrt[4]{\sqrt[3]{2^{2}}}$ equals

Fill in the blanks to make the following statement true:
$\sqrt{1 \frac{25}{144}} = \ldots$