If b is positive, what is the value of b in the geometric sequence 16, a, 18, b?
If the common ratio is r (assumed to be positive), then a = 16·r
and 18 = (16·r)·r = 16·r2 ---> 16·r2 = 18 ---> r = sqrt(18/16)
then b = 18·r = 18·sqrt(18/16)
