#1**+5 **

After 'mathing' for a while you will remember a lot of perfect squares 4 9 16 25 36 etc

the square root of those are 2 3 4 5 6

For larger numbers that are not perfect squares you will have to use a calculator ...

sqrt 149 =

sqrt(149) = 12.206555615733703

ElectricPavlov
Feb 23, 2017

#2**0 **

If you mean HOW to calculate it by hand, there is a procedure called "Newton's method" that you can use, and it converges quadratically, i.e., the number of accurate digits is doubled after each iteration. This is the formula: 1/2{n/a + a}, where n=the number that your trying to find the square root of, a =your first "guess". The result of the 1st iteration is plugged into the formula to get the 2nd approximation and so on. About 4-5 iterations will give you very accurate square root, perhaps to 15 - 20 decimal places of accuracy. Try it!!. Warning: It can get laborious and tedious!!.

Guest Feb 23, 2017