Question

Am i right


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Answer 1

\(\sqrt{4}\) is a rational number.
\(-2\pi\) is not a rational number.
\(-2 \sqrt{7}\) is not a rational number.
\(78.80\) is a rational number.
\(-47.86\) is a rational number.

Answer 2

So you are right on all except \(\sqrt{4}\).

Answer 3

@skatey do you understand?

Answer 4

thanks

Answer 5

not completely

Answer 6

No problem, glad to help.

Answer 7

why is sqrt 4 rational?

Answer 8

Surprisingly there is a Wikipedia page devoted to that reason:
https://en.wikipedia.org/wiki/User:wingspanlyon/Square_root_of_4
Here is a page that explains it better though:
http://www.mathsisfun.com/numbers/irrational-finding.html
Scroll to where it says: "Try Some More Numbers"

Answer 9

wiki dont work

Answer 10

ok thanks

Answer 11

Quoted from the mathisfun link:
"How about 4? 4 is 4/1 = 22
Yes! The exponent is an even number! So 4 can be made by squaring a rational number.
The square root of 4 is rational"