Question: A student claims that the decimal expansion of the number sqrt(18) is rational because 18 is divisible by 9 . Evaluate the student's reasoning and identify the correct conclusion.
A) The student is correct because 18 is divisible by 9, making sqrt(18) rational
B) The student is incorrect because divisibility  does not determine rationality of square roots
C) the student is correct because sqrt(18) can be written as 3sqrt2 , and 3sqrt2 is rational
D) The student is incorrect because 18 is not a perfect square , making sqrt18 irrational
Correct answer: D
Grade: 8 | Topic: Number System | Difficulty: Hard | Standard: 8.NS.A.2