Find the area bounded by the x-axis and the arc of the cycloid $\displaystyle x=a(\theta-\sin\theta)$, $\displaystyle y=a(1-\cos\theta)$ between $\displaystyle \theta =0$ and $\displaystyle \theta=2\pi$, rotated about the x-axis.

My problem is that I don't have the formula for the volume for parametric equations.

For Cartesian equations :$\displaystyle V=\int ^a_b (\pi y^2) dx$

But I don't know how to adapt this for parametric equations.

Thanks!