Hello, Rashel,
The geometric mean of two numbers is the square root of their product. 6 is one number and we'll say the other number is X.
The product is 6*X, We know the square root of this value is 4, the remetric mean.
(6*X)1/2 = 4
6*X = 16
X = (16/6), or (8/3).
This sounds awful - who needs fractions like this in their life? But let's see if it works:
(6*(8/3))1/2
(2*8)1/2
(16)1/2 = 4
It seems to work,
Bob