How do you learn square rooting?

Answer 1

Th84.64ree methods;-

1. use the surd sign on a calculator e.g. (sqrt) / 4 = +/- 2

2. Use a rather complex arithmetica system of long division.

3. Use a time consuming but simpler method. e.g. sqrt(90)

To answer

We know sqrt(81) = 9

Sqrt(100) = 10

Since '90' is between 81 and 100 , then the square root is between '9' & '10'

Then by trial and error

9.1^(2) = 82.81 too small

9.2^(2) = 84.64 too small

9.3^(2) = 86.49 too small

9.4^(2) = 88.36 too small

9.5^(2) = 90.25 too big

So we need a decimal number between 9.4 & 9.5 say 9,45

9.45^(2) = 89.3025 too small

9.46^(2) = 89.4916 too small

et. seq.

The acutal value is sqrt(90) = 9.486832981....

In Surd form sqrt(90) = sqrt(10 x 9) = sqrt(10) X sqrt(9) = sqrt(10) x 3

or

3 sqrt(2) sqrt(5)

Since '2' & '5' are prime numbers, their respective square roots are Irrational Numbers.

Answer 2

Learn your squares first... 1*1 = 1 2*2 = 4 3*3 = 9 4*4 = 16 now lets say you want the square root of 10 what do we already know? its slightly greater than 3 not by much but slightly so I would write a 3 down. From there I usually just add a decimal or two in my mind and slowly increment it. 3.1...9.61 close.. 3.15... 9.922. closer... basically its a pain if you want to get the exact answer but you can get very close. Just look at the number you want to take the square root of and figure out where it would be in the square list.