A conical shaped cup, when filled with ice-cream, forms into the shape of a hemisphere at its open end. What is the volume of the ice cream, if the radius of the base of the cone is 3 cm and the vertical height of the cone is 7 cm?
1
\(\rm \frac{2754}{21} \ cm^3\)
2
\(\rm \frac{2574}{21} \ cm^3\)
3
\(\rm \frac{2504}{21} \ cm^3\)
4
\(\rm \frac{2547}{21} \ cm^3\)