If $\sqrt{5} = 2.24$; the value of $\sqrt{20}$ is:

1. 1.12

2. 4.48

3. 2.24 x 4

4. none of the above

If $\sqrt{27.8} = 5.27$; the value of $\sqrt{2780}$ is:

1. 527

2. 52.7

3. 0.527

4. none of the above

n is the least natural number that must be subtracted from 23 so that the resulting number is a perfect square, the value of n is:

1. 7

2. 2

3. 5

4. -7

Find the square root of 4761.