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

If 4 quantities are in proportion and the second is a mean proportional between the third and fourth, prove that the third will be a mean prop. between the first and second.

From A Review of Algebra by Rivenburg, Romeyn Henry

To this important proposition there is one corollary of particular interest, namely, The perpendicular from any point on a circle to a diameter is the mean proportional between the segments of the diameter.

From The Teaching of Geometry by Smith, David Eugene

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

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

From A Review of Algebra by Rivenburg, Romeyn Henry

When 5 and 20 are given, x is a mean proportional when in 5, x, 20, 5 is to x as x to 20.

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