Which of the following rational numbers is not between √3 and √6?

A. 1.8
B. √4
C. 1 5
D. 2

To solve this, we need to find the values of √3 and √6 and determine which rational number is not between them.

√3 is a little more than 1.7 (approximately 1.732).
√6 is a little less than 2.5 (approximately 2.449).

A. 1.8 is between 1.7 and 2.5, so it is between √3 and √6.
B. √4 is equal to 2, which is between √3 and √6.
C. 1 5 is equal to 1.5, which is between √3 and √6.
D. 2 is equal to √4, which is between √3 and √6.

Therefore, the correct answer is: None of the rational numbers given are not between √3 and √6.

To determine which of the given rational numbers is not between √3 and √6, let's compare each number to the given range.

√3 ≈ 1.732 and √6 ≈ 2.449

A. 1.8 is between √3 and √6 because 1.732 < 1.8 < 2.449.
B. √4 is equal to 2, and it is between √3 and √6 because 1.732 < 2 < 2.449.
C. 1 5 is not specified, so we cannot determine if it is between √3 and √6.
D. 2 is not between √3 and √6 because 1.732 < 2 is not true.

Thus, the rational number that is not between √3 and √6 is D. 2.