jmc

Dividing by $36$ gives the standard form of the equation of this ellipse, $$\frac{x^2}{4}+\frac{y^2}{36}=1.$$Then, the semimajor and semiminor axes have lengths $\sqrt{36}=6$ and $\sqrt{4}=2,$ respectively. By the area formula for an ellipse, the area of the ellipse is $6\cdot 2\cdot \pi =\boxed{12\pi }.$