mean proportional

American  

noun

Mathematics.

1. (between two numbers a andb ) a number x for which a/x = x/b .

   The number 3 is a mean proportional between 1 and 9.

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Etymology

Origin of mean proportional

First recorded in 1565–75

Example Sentences

Define ratio, proportion, mean proportional, third proportional, fourth proportional.

From A Review of Algebra by Rivenburg, Romeyn Henry

Was his confounding two mean proportionals with one mean proportional found twice over a trick of the same intent? if so, it beats cockfighting.

From A Budget of Paradoxes, Volume II by Smith, David Eugene

Then the whole line DC is 141,289; and CP, which is a mean proportional between DC and CN, since MD touches the Ellipse, will be 105,032.

From Treatise on Light by Huygens, Christiaan

Then x - 5 is a mean proportional between x - 9 and x, from which we find that x equals 25.

From Amusements in Mathematics by Dudeney, Henry Ernest

Assuming π to be 3⅛, he finds out by working instance after instance that the mean proportional between one-fifth of the area and one-fifth of eight is the radius.

From A Budget of Paradoxes, Volume II by Smith, David Eugene