To determine between which two values the square root of 21 lies, we first need to find the perfect squares around 21.
The perfect squares closest to 21 are:
- \(4^2 = 16\)
- \(5^2 = 25\)
This means that: \[ 4 < \sqrt{21} < 5 \]
Next, we can square the numbers in the options to find which interval contains 21.
Calculating the squares of 4.1 and 5.1, we find:
- \(4.1^2 = 16.81\)
- \(5.1^2 = 26.01\)
Since \(16.81 < 21 < 26.01\), this confirms that \(4.1\) and \(5.1\) are the boundaries.
Thus, the correct interval is:
B. square root of 21 is between 4.1 and 5.1.