Answer
The required equation is $x=ky{{z}^{2}}$ and the value of $y$ is $\frac{x}{k{{z}^{2}}}$.
Work Step by Step
As the value of $x$ varies jointly as $y$ and ${{z}^{2}}$ , we have $x=ky{{z}^{2}}$
Where $k$ is a constant
Now, solve the above equation for $y$.
Divide $x=ky{{z}^{2}}$ by $k{{z}^{2}}$.
$y=\frac{x}{k{{z}^{2}}}$
