Answer
$z\propto x\times y$
$z=k\times x\times y$
As one quantity increases, many other quantities will also increase.
Work Step by Step
Variation formulas define the relation between two quantities such that if one quantity varies, we will know how that affects the other quantity.
The equation provided is: $z=k{{x}^{2}}\sqrt{y}$
The above equation is a case of joint variation as in joint variation many variables vary directly as soon as one or two variables vary in a system.
