Question

16 < 21 < 25, so √21 is between and. this means that √21 is between 4 and 5.

Explanation:

Step1: Recall square - root property

We know that if \(a^2 < b < c^2\), then \(a<\sqrt{b}

Step2: Find the square - roots of 16 and 25

Since \(4^2 = 16\) and \(5^2=25\), and \(16 < 21 < 25\).

Answer:

4, 5