In order to identify if the given numbers are perfect cube, it is necessary to determine if there is a way of writing the given numbers as a number powered to 3.
27
This number can be written as 3³ = 3 x 3 x 3 = 27
Hence, it's a perfect cube
1
This number can be written as 1³ = 1 x 1 x 1 = 1
Hence, it's a perfect cube
1,000
This number can be written as 10³ = 10 x 10 x 10 = 1,000
Hence, it's a perfect cube
90
There is no way to write this number as a number powered to 3.
Then, it is not a perfect cube