If the fiber contains about six nucleosomes per 10 nm of length, what is the approximate compaction ratio achieved?

Each fibre is about 30 nm and this structure gives an approximate compaction ratio of 40. Then, each nucleosome gives a compaction ratio of 6. If we are considering that there are 6 nucleosomes per 10 nm, then, in those 10 nm we get a compaction ratio of 6×6=36. Considering now that we are taking a fibre into account - 30 nm long - we need to multiply 36 (compaction ratio in 10 nm of a fiber) by 3 (10nm×3=30nm). 36×3=108
The approximate compaction ratio achieved is of 108.