Question 145
On a spherical planet with diameter $10,000~\mathrm{km}$, powerful explosives are placed at the north and south poles. The explosives are designed to vaporize all matter within $5,000~\mathrm{km}$ of ground zero and leave anything beyond $5,000~\mathrm{km}$ untouched. After the explosives are set off, what is the new surface area of the planet, in square kilometers?