Find the square numbers and see which ones 54 lies between
1, 4, 9, 16, 25, 36, 49, 64.
It lies between the two square numbers 49 and 64.
But you want the square root.
So find the square root of 49 and 64.
7 and 8.
So the square root of 54 is between 7 and 8.
Hope this helps.