If someone can help me please :)))

The radius of the earth is two times the radius of the moon. what fraction of the volume of the earth is the volume of the moon?

I’m confused on how to work the pie charts

The price of a visit to the dentist is \$50$50. if the dentist fills any cavities, an additional charge of \$100$100 per cavity gets added to the bill. if the dentist finds nn cavities, what will the cost of the visit be?