Solution: The volume of a hemisphere is $ \frac23\pi (3x)^3 = \frac23\pi 27x^3 = 18\pi x^3 $. The cylinder's volume is $ \pi x^2 \cdot 3x = 3\pi x^3 $. The ratio is $ \frac18\pi x^33\pi x^3 = \boxed6 $. - Portal da Acústica