Here the number is 1080.
We need to divide this in a ratio of 4:1.
This means we have to divide it in 5 parts.
The first part is 4 parts out of 5 parts
So we have

The second part is 1 part out of 5 parts
So we have

Now
864 + 216 = 1080
Our division is correct.
The two parts in a ratio of 4:1 are 864 & 216.