Let the required mean proportional be x.
So, 0.06, x, and 0.96 are in continued proportion.
So, 0.06:x::x:0.96
In a continued proportion, the product of the extremes is equal to the square of the third proportional.
So, x2 = 0.06 × 0.96
x=√0.06×0.96=√0.0576=0.24