$8.88 \times 88.8 \times 88 = ?$

If $\frac{a^{2}+b^{2}}{c^{2}+d^{2}}=\frac{a b}{c d},$ then find the value of $\frac{a+b}{a-b}$ in terms of $c$ and $d$ only.

Which of the following statement$(s)$ is/are $TRUE$?
$I.$ $\sqrt{11}+\sqrt{7} < \sqrt{10}+\sqrt{8}$
$II.$ $\sqrt{17}+\sqrt{11} > \sqrt{15}+\sqrt{13}$

If $ab + bc + ca = 0$,then the value of $\left(\frac{1}{a^2 - bc} + \frac{1}{b^2 - ca} + \frac{1}{c^2 - ab}\right)$ is

Which of the following are in descending order of their value?

$12.1212 + 17.0005 - 9.1102 = ?$