What is the Square root of 7750 is ?to the nearest whole number

Twelve (12).
.
12 squared is 144, 13 squared is 169. 148 is closer to 144 than to 169, and the square root of 148 is about 12.166.

Twelve (12).

To do them it REALLY helps if you remember Perfect Squares.it will make you quicker at doing these problems.

From this page http://www.gmathacks.com/mental-math/estimating-square-roots.html
I have copied a section below.

For these problems.....
you don't need the exact answer! An approximation is good enough

. Memorize Squares
For all sorts of reasons, you should memorize perfect squares at least up to 12^2 = 144. It helps to know additional round numbers, such as 15^2 = 225 and 25^2 = 625.
Once squares are burned into your memory, estimating square roots is easy. Let's go back to the square root of 39. The nearest perfect squares are 36 and 49, which are squares of 6 and 7, respectively. Thus, the square root of 39 is somewhere between 6 and 7. Since 39 is closer to 36 than to 49, the square root of 39 is closer to 6 than 7.
Sure enough, the square root of 39 is about 6.24. You will never see a problem on the GMAT where you need to know that the square root of 39 is 6.24. But you may well need to know that the square root of 39 is a little bigger than 6.

We all had to learn these at one time.

Give it a go friend :) You won't regret it.later on in life.

The square root is the second function of the "3" key. To calculate the square root of 3, press 3 2ndF 3 =

Press 2nd then F--D key(its means left arrow key or left key from zero)

Press 2nd [square-root], enter the number, press ) =

For example, to calculate the square root of 5, press 2nd [square-root] 5 ) =

The square root of a negative number is an imaginary number, and the TI-30XA does not deal with imaginary numbers.

However, the square root of -x is equal to i times the square root of x. So, to calculate the square root of -4, for example, press 4 square_root = and read 2. Thus the square root of -4 is 2i.

It may be that you have somehow changed to a 'mode' that only shows integer values.

Try pressing the green button, then 5, then 9. Then try the calculation again.

If this fails, you can use Google as a calculator - search Google for sqrt(0.4053) and see what happens.. :-)

Use the toggle button above the enter key. It looks like 2 arrows

roots of x2+3x+1=0