You need to find out if 57 can be divided evenly by a number other than 1 and 57.
57 is odd, so it is not divisible by 2.
The digits of 57 are 5 and 7. Add 5 + 7 to get 12. Since 12 is divisible by 3 (12/3 = 4), then 57 is also divisible by 3.
57/3 = 19
19 is a prime number, so the only factors of 57 are 1, 3, 19, 57.
57 rows can be divided into 19 sections of 3 rows each or 3 sections of 19 rows each.