The approximate total surface area of Earth is 5.1 × 108 km2. All the salt water on Earth has an approximate surface area of 352,000,000 km2, and all the freshwater
on Earth has an approximate surface area of 9 × 106 km2

a) How much of Earth’s surface is covered by water, including both salt and fresh
water? Write your answer in scientific notation.

b) How much of Earth’s surface is covered by land? Write your answer in scientific
notation.

c) Approximately how many times greater is the amount of Earth’s surface that is
covered by water compared to the amount of Earth’s surface that is covered by
land?