is between what two numbers?

We write down, or just think through, the list of squares
and their square roots:

1² = 1, therefore  = 1
2² = 4, therefore  = 2
3² = 9, therefore  = 3
4² = 16, therefore  = 4
5² = 25, therefore  = 5
6² = 36, therefore  = 6
7² = 49, therefore  = 7
8² = 64, therefore  = 8
9² = 81, therefore  = 9
10² = 100, therefore  = 10

That's far enough. We know from that list that 
 is between  which is 9 and  which is 10.

Therefore the answer is C).

Edwin