Direct Variation Calculator
Find the constant k and a new y value for the direct variation model y=kx.
Formula
k=y₁/x₁; y₂=kx₂; x₁≠0.
Constant k ≈ (6)÷(2) · New y₂ ≈ (3)×(5)
How to use
- Enter a known pair x₁, y₁ with x₁ nonzero.
- Enter the new x₂.
- Read k and the predicted y₂.
Examples
- x₁=2, y₁=6 and x₂=5 give k=3 and y₂=15.
Frequently asked questions
May k be negative?
Yes. Direct variation permits a negative proportionality constant.
Why must x₁ be nonzero?
A pair with x₁=0 cannot uniquely determine k by division.
Does this fit a general line?
No. Direct variation has zero intercept and passes through the origin.
Sources
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