The volume of a hemisphere is $2425\frac{1}{2} {\mathrm{cm}}^3$. If its curved surface area of hemisphere is $k {\mathrm{cm}}^2$ then write the value of $k$. $(\text{Use} \mathrm{\pi }=22/7)$

The internal and external diameters of a hollow hemispherical vessel are $21 \mathrm{cm}$ and $25.2 \mathrm{cm}$, respectively. The cost of painting $1 {\mathrm{cm}}^2$ of the surface is $10 \mathrm{paise}$. If the total cost to paint the vessel all over is $₹k$, then write the value of $k$ rounded off to two decimal places. $(\text{Use} \mathrm{\pi }=22/7)$

Total surface area of a solid hemisphere is $462 {\mathrm{cm}}^2,$ and if its volume is $k {\mathrm{cm}}^3$, then find the value of $k$ rounded off to two decimal places.$(\text{Use} \mathrm{\pi }=22/7)$