Constant of Variation

Pronunciation: /ˈkɒn stənt ʌv ˌvɛər iˈeɪ ʃən/ ?

The constant of variation is the ratio by which the input and output vary in direct variation or direct proportion. Constant of variation means the same thing as constant of proportion.

The general equation for direct variation is the linear equation, y = kx where k is the constant of variation (or constant of proportion). The constant of variation is also the slope of the line representing the relationship between input and output.

In the equation y = 3x, the constant of variation is 3.

In the equation r = 0.6t, the constant of variation is 0.6.


  1. Lyman, Elmer A.; and Darnell, Albertus. Elementary Algebra, pg 448. American Book Company, 1917. (Accessed: 2010-01-20).
  2. Reitz, H. L.; and Crathorne, A. R.. College Algebra, revised edition, pg 97. Henry Holt and Company, 1919. (Accessed: 2010-01-20).

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Constant of Variation. 2008-03-04. All Math Words Encyclopedia. Life is a Story Problem LLC.


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2008-03-04: Added Growth to See Also (McAdams, David.)
2008-02-04: Added examples (McAdams, David.)

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