If the product of three continued proportional positive numbers be 64, then their mean proportional is _____ .

Explanation

Let the three positive numbers which are in continued proportional be a, b, c.
` :. a/b = b/c " or, " b^(2) = ac ` ………….(1)
As per question, `abc = 64 " or, " b xx ac = 64`
or, ` b xx b^(2) = 64 " or, " b^(3) = 4^(3) = 4^(3) :. B = 4`.
` :. ` the required mean - proportion is `underline4`