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

Each of the other sides is the mean proportional between the hypotenuse and the segment of the hypotenuse adjacent to that side.

From The Teaching of Geometry by Smith, David Eugene

Then the whole line CZ is 139,655; and CS, which is a mean proportional between CZ and CO will be 93,410.

From Treatise on Light by Huygens, Christiaan

The second of three numbers is a mean proportional between the other two.

From A Review of Algebra by Rivenburg, Romeyn Henry

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

The perpendicular is the mean proportional between the segments of the hypotenuse.

From The Teaching of Geometry by Smith, David Eugene