The Math Forum

Ask Dr. Math - Questions and Answers from our Archives
Associated Topics || Dr. Math Home || Search Dr. Math

What is the Square Root of 8?

Date: Thu, 13 Jun 1996 14:58:56 +0100
From: dhautree
Subject: square routes

What is the square route of 8?

Date: Thu, 13 Jun 1996 21:29:18 -0400 (EDT) 
From: Dr. Tom
Subject: Re: square routes

>what is the square route of 8?

First off, it's "square root", not "square route". 

If you just punch it into your calculator, you'll get something like: 
2.8284271247461900976, and this is not even EXACTLY right.

The square root of a number is some other number which, when 
multiplied by itself, gives the original number. 

The square root of 9 is 3 since 3 times 3 is 9. 

If you multiply the number 2.82... above by itself, you don't get 
quite 8; you get 7.99999999999999999998... But by adding more 
and more decimal places, you can get numbers closer and closer to 
the real square root. 

This is not unusual -- what is 1/3, after all? Is it .333, or 
.33333333, or .333333333333333333333333? It's none of those, 
but the last is quite close to the exact value. 

You can find approximate square roots by trial and error: 
for sqrt(8), 2 is too small and 3 is too big, so try 2.5, 2.6, 2.7, 2.8, 
and 2.9. You'll find the answer is between 2.8 and 2.9. So then try 
2.81, 2.82, ... et cetera, to see that it's between 2.82 and 2.83, and 
so on. 

Or you can just use a calculator or computer! 

-Doctor Tom, The Math Forum

Associated Topics:
Middle School Square Roots

Search the Dr. Math Library:

Find items containing (put spaces between keywords):
Click only once for faster results:

[ Choose "whole words" when searching for a word like age.]

all keywords, in any order at least one, that exact phrase
parts of words whole words

Submit your own question to Dr. Math

[Privacy Policy] [Terms of Use]

Math Forum Home || Math Library || Quick Reference || Math Forum Search

Ask Dr. MathTM
© 1994- The Math Forum at NCTM. All rights reserved.