Which is a rational number?
a.square root of 8
b.square root of 16
c. square root of 18
d. square root of 20

Please give answer and explain.

Thanks :D

Question

Which is a rational number?
a.square root of 8
b.square root of 16
c. square root of  18
d. square root of 20

Please give answer and explain.

Thanks :D

anonymous · Answer

do you know what a rational number is

anonymous · Answer

No I do not

anonymous · Answer

number with no fraction, no?

anonymous · Answer

well if you find the square root of each number which is the only one that will square completely

anonymous · Answer

in other words 
$$\sqrt{a}$$ is NOT a rational number unless $a$ is a perfect square, like say 4,9,16,25,...

anonymous · Answer

ok so, only one squares completely so is that the answer?

anonymous · Answer

so for example 
$$\sqrt{25}$$ is rational because 
$$\sqrt{25}=5$$ but 
$$\sqrt{8}$$ is not rational because 8 is not a perfect square

anonymous · Answer

Ok I get it thanks :D