Geometric mean

geo mean = #of #s√#*#

                 we have 2 numbers

so 2√#*#

    2 is just a regular sq rt as opposed to cube root etc

so √#+#

are numbers are 1/4 and 100

so √(1/4*100) = 

√25

=5

The geometric mean is defined as the nth root of the product of n numbers

So, the geometric mean  of  100 and 1/4  equals the square root of their product =

√[ 100 * (1/4)  ]  =

√ [ 25]   = 

5