Analysis: Known: 30? =900,3 1? =96 1, so there is: 30 < √ 925 < 3 1, that is, the number obtained by squaring 925 is not an integer, between 30 and 3 1. There is also 925=25×37, where 25=5×5 and 37 is not a square number, so it cannot be squared.

So we can work out: √925=5√37.

Common square number:

1 1^2= 12 1

12^2= 144

13^2= 169

14^2= 196?

15^2=225 ?

16^2=256?

17^2=289?

18^2=324?

19^2=36 1?

20^2=400 ?

Extended data:

Characteristics of complete square numbers:

1, essence: after the prime factor is decomposed, each prime factor is even.

2. Nature: I mean odd cause.

3. In the factorization of a complete square number, the exponent of each prime factor is even, and vice versa.

4. The number of factors of a complete square number is odd, and vice versa.

5. The number of factors of 3 must be the square of prime numbers.

Forward derivation: If you know the unit number of a natural number n, then you also know the unit number of N2.

Backward derivation: Knowing the unit number of N2, we can estimate the unit number of natural number n..