The approximate total surface area of Earth is 5.1×108

Question

km 2
. All the salt water on Earth has an approximate surface area of 352,000,000 km 2
. All the freshwater on Earth has an approximate surface area of 9×106
km 2




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

Answer 1

To find the total surface area of Earth's water, we need to add the surface area of saltwater and freshwater:

1. Surface area of saltwater: \( 352,000,000 , \text{km}^2 \) or \( 3.52 \times 10^8 , \text{km}^2 \)
2. Surface area of freshwater: \( 9,000,000 , \text{km}^2 \) or \( 9 \times 10^6 , \text{km}^2 \)

Now we add these two:

\[ 3.52 \times 10^8 , \text{km}^2 + 9 \times 10^6 , \text{km}^2 \]

To add these, we can write \( 9 \times 10^6 \) in the same power of ten as \( 3.52 \times 10^8 \):

\[ 9 \times 10^6 = 0.009 \times 10^8 , \text{km}^2 \]

Now we can add:

\[ 3.52 \times 10^8 , \text{km}^2 + 0.009 \times 10^8 , \text{km}^2 = (3.52 + 0.009) \times 10^8 , \text{km}^2 = 3.529 \times 10^8 , \text{km}^2 \]

Thus, the total surface area of Earth's water is approximately:

\[ \boxed{3.529 \times 10^8} , \text{km}^2 \]