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

Find a mean proportional between 4 and 16; 18 and 50; and 3.

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

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

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