How to Use Direct Variation Calculator
The Direct Variation Calculator has two modes. In solve mode, enter exactly two of x, y, and k. The Direct Variation Calculator solves the missing value from y = kx. In check mode, enter multiple x, y pairs to test whether y / x is constant.
The Direct Variation Calculator warns when x is zero because y / x would be undefined. It also shows the ratio list so you can see why a data set does or does not fit direct variation.
Formula & Theory — Direct Variation Calculator
The Direct Variation Calculator uses y = kx, where k is the constant of variation. If x and y are known, k = y / x. If x and k are known, y = kx. If y and k are known, x = y / k.
A relationship is direct variation only when the same k works for every data pair. The Direct Variation Calculator makes that constant visible instead of only returning a yes or no answer.
Use Cases for Direct Variation Calculator
Use the Direct Variation Calculator for algebra lessons, proportional reasoning, unit-rate problems, scale models, recipe scaling, physics proportionality, and checking tables of values. The Direct Variation Calculator is especially helpful for students learning how constants of variation behave.