**1.183*10^11 square km**

The total area is $4\pi \sum_0^{100}(3000+120n)^2$.

We ask Wolfram Alpha (leaving out the 4$\pi$):

[![enter image description here][1]][1]

Now we just have to multiply the result by 4$\pi$:

4$\pi$ * 9417240000 = 1.183*10^11 square km.

QED.

  [1]: https://i.sstatic.net/AJnodY98.png