You have the square root of the following number:
√450
In order to know in between which numbers the square root is, you consider
the following results:
21² = 441 -> √441 = 21
22² = 484 -> √484 = 22
as you can notice, 441 and 484 have square root that are in between 21 and 22.
√450 is a number in between 21 and 22