Hey there !
As you've already mentioned all the necessary theory part , me will show the calculations and final answer ,
[tex] \dfrac{1.09 \times {10}^{12} }{2.18 \times {10}^{10} } \: = \: \dfrac{ {10}^{2} }{2} = \dfrac{100}{2} = 50[/tex]
Hence , 50 moons can fit inside earth
Hope it helps you :)
