Joint Variation Calculator

This calculator works out joint variation, where one quantity depends on the product of two others, using the formula z = k x y. It is common in maths and science: the area of a triangle varies jointly with its base and height, and many physics formulas tie an outcome to two driving quantities multiplied together, which is what separates joint variation from simple direct variation. To use it, enter a known set of x, y and z, values you already know fit the relationship, and the calculator divides z by the product of x and y to find the constant k. Then enter a new x and y, and it applies z = k x y to predict the matching z. You get three results: the full formula with your constant filled in, the constant k itself, and the predicted z for your new values, all updating instantly as you type so you can test several pairs without re-entering anything. It suits students checking homework, teachers preparing examples, and anyone wanting a fast, reliable answer instead of working the algebra by hand. Just make sure your known x and y are not zero, since dividing by zero has no answer, and remember results are rounded for display. A worked example and the full formula are set out below if you want to follow the method step by step.

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