Question 1147845
The rest of the body is L
1:3 as x:20
Cross-multiply and 3x=20 and x=6 2/3 inches 
the ratio of the head to the length of the WHOLE body (head and length) is 6 2/3 to 26 2/3 or 1:4

That compares to 1:9 in the adult.  Encephalization (head growth) occurs faster than the rest of the body, so the head is much bigger than adult proportions in newborns, bigger in childhood, before finally reaching adulthood. Most of the head growth appears before and shortly after birth; the body requires a longer period of time.