If b is positive, what is the value of b in the geometric sequence 16, a, 18, b?
Let r be the common ratio
So
18/16 = r^2
9/8 = r^2
3 / (2sqrt 2) = r
b = 18 ( 3 / (2sqrt 2) ) = 27 / sqrt 2 = 27 sqrt (2) /2 = 13.5*sqrt (2)
