Find the square roots of the following numbers correct up to $2$ places of decimal.

$23.1$

Arrange the following in the descending order $\left(\sqrt{23}-\sqrt{21}), (\sqrt{19}-\sqrt{17}), (\sqrt{21}-\sqrt{19}\right)$.

Consider the following numbers:

$$\begin{gathered} 1. 2222 \\ 2. 11664 \\ 3. 343343 \\ 4. 220347 \end{gathered}$$

Which of the above are not perfect squares?

Evaluate $\sqrt{0.9}$ correct up to two places of decimal.

Evaluate $\sqrt{2.8}$ correct up to two places of decimal.

Find the least number which must be added to $8400$ to obtain a perfect square. Find this perfect square and its square root.

The value of $\sqrt{1.96}\times \sqrt{0.04}$ is

Evaluate: $\sqrt{0.2916}$

Evaluate: $\sqrt{156.25}$

Evaluate $\sqrt{3}$ up to two places of decimal.

Find the length of each side of a square whose area is equal to the area of a rectangle of length $13.6$metres and breadth $3.4$ metres.

By which least number should the following number be divided to make it a perfect square?

$11520$

Find the least number that must be added to the following number to make it a perfect square.

$9352.$