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## #1 2017-05-30 00:22:51

Zeeshan 01
Member
Registered: 2016-07-22
Posts: 648

### Square root

Hi;
How to take square root of number like 0.2, 0.34,0.23455 etc without calculator
Sqrt of 0.2 is  ???
0.707 multiple b 0.707

MZk

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## #2 2017-05-31 03:02:28

bob bundy
Registered: 2010-06-20
Posts: 8,354

### Re: Square root

hi Zeeshan 01

If you google "square root without a calculator" you'll find loads of sites offering methods.  They all need some arithmetic however.  How's your long division?

A method I rather like is this:

Let's say the number is N.  Take a guess for the square root, say x, and do N÷x = y.

If x was too small then y will be too big and vice versa.  So work out (x+y)/2 and make this your next guess.  This 'homes in' on the root quite quickly.

eg.  N=50 x = 7

y = 50/7 = 7.14.....

(x+y)/2 =7.0714...

new x = 7.0714....
new y = 7.070707
new(x+y)/2 = 7.071068

This is accurate to 5 decimal places.

Bob

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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## #3 2017-05-31 05:58:29

Zeeshan 01
Member
Registered: 2016-07-22
Posts: 648

### Re: Square root

bob wrote:

Pretty Good

Last edited by Zeeshan 01 (2017-05-31 06:00:23)

MZk

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## #4 2017-05-31 06:02:10

Zeeshan 01
Member
Registered: 2016-07-22
Posts: 648

### Re: Square root

Sqrt of 0.2 is  ???
Can you put this info in your method??

MZk

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## #5 2017-05-31 06:32:02

bob bundy
Registered: 2010-06-20
Posts: 8,354

### Re: Square root

here we go:

Bob

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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## #6 2017-05-31 20:18:11

Zeeshan 01
Member
Registered: 2016-07-22
Posts: 648

### Re: Square root

??? N is 0.2 and how x is 1 and y is 0.2

MZk

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## #7 2017-05-31 21:15:05

bob bundy
Registered: 2010-06-20
Posts: 8,354

### Re: Square root

Zeeshan 01 wrote:

N is 0.2 and how x is 1 and y is 0.2

Sqrt of 0.2 is  ???

So that makes N=0.2

x is a guess.  It can be any number.  If you chose a value close to the correct answer, then you'll get to an accurate answer more quickly.   But any number will work so I chose x = 1.

Then you calculate y using the formula y = N/x= 0.2/1 = 0.2

Then you calculate the mean average of x and y = (1+0.2)/2 = 1.2/2 = 0.6

That becomes the new x. Repeat until x and y are so close to each other that (x+y)/2 gives the same result.  That's the square root.

Bob

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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## #8 2017-05-31 22:04:16

Zeeshan 01
Member
Registered: 2016-07-22
Posts: 648

Hmm

MZk

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## #9 2017-05-31 22:06:16

Zeeshan 01
Member
Registered: 2016-07-22
Posts: 648

### Re: Square root

You know proportions direct and indirect??

MZk

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## #10 2017-06-01 00:01:45

Member
From: Planet Mars
Registered: 2016-11-15
Posts: 766

### Re: Square root

Do you need help with that?

Practice makes a man perfect.
There is no substitute to hard work
All of us do not have equal talents but everybody has equal oppurtunities to build their talents.-APJ Abdul Kalam

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## #11 2017-06-02 15:19:56

Zeeshan 01
Member
Registered: 2016-07-22
Posts: 648

### Re: Square root

So work out (x+y)/2 and make this your next guess
How x become (x+y)divde by 2

MZk

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## #12 2017-06-03 14:40:24

Zeeshan 01
Member
Registered: 2016-07-22
Posts: 648

### Re: Square root

How x become (x+y)divde by 2

MZk

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