Which if the following is a rational number?

A) This is a rational number since the square root of 1 is 1. (sqrt(1) = 1, or 1^2 = 1). We can write "1" as 1/1 showing that it is rational.

B) This is NOT a rational number. We cannot write sqrt(2) as a fraction of two whole numbers.

C) Similar to choice B, we can't write sqrt(3) as a ratio of two integers.

D) Similar to B and C. sqrt(5) is NOT rational

We say that the numbers for B, C, D are irrational. Any real number that is not rational is considered irrational.



The answer is therefore choice A