$\sqrt{176+\sqrt{2401}} = ?$

In the following questions,two equations numbered $I$ and $II$ are given. You have to solve both the equations and give the answer.
$I: \frac{13}{\sqrt{x}} + \frac{9}{\sqrt{x}} = \sqrt{x}$
$II: y^4 - \frac{(13 \times 2)^{9/2}}{\sqrt{y}} = 0$

Square root of $(272^{2}-128^{2})$ is

Find the smallest number by which $216$ should be divided to make the result a perfect square.

$\frac{\sqrt{4375}}{\sqrt{7}} = ?$

$\frac{250}{\sqrt{?}}=10$