Three-fifth of the square of a certain number is $126.15$. What is the number?

$\sqrt{\frac{0.256 \times 0.081 \times 4.356}{1.5625 \times 0.0121 \times 129.6 \times 64}} = ?$

$\sqrt{11449} \times \sqrt{6241} - (54)^{2} = \sqrt{?} + (74)^{2}$

The value of $\frac{1+\sqrt{0.04}}{1-\sqrt{0.1}}$ is nearly equal to

Given that $\sqrt{20} = 4.472$,find the square root of $2 \frac{2}{9}$ up to two places of decimals.

In the following questions,two equations numbered $I$ and $II$ are given. You have to solve both the equations and give the answer.
$I$: $5x^2 - 18x + 9 = 0$
$II$: $3y^2 + 5y - 2 = 0$