Question

the planet earth has land area of $5.761 \times 10^8$ square miles and surface area of $1.966 \times 10^9$ square miles. how many square miles of the earths surface are not land?

Explanation:

Step1: Rewrite to same exponent

Rewrite $1.969 \times 10^8$ as $19.69 \times 10^7$

Step2: Subtract land area from surface area

$19.69 \times 10^7 - 5.761 \times 10^7 = (19.69 - 5.761) \times 10^7$

Step3: Calculate coefficient difference

$19.69 - 5.761 = 13.929$

Step4: Adjust to proper scientific notation

$13.929 \times 10^7 = 1.3929 \times 10^8$ square miles

Note: Correction: Step 2 surface area is $1.969 \times 10^8 = 19.69 \times 10^7$, land area $5.761 \times 10^7$. Subtraction: $19.69 - 5.761 = 13.929$, so $13.929 \times 10^7 = 1.3929 \times 10^8$ square miles. Final correct answer is $1.3929 \times 10^8$ square miles.

Corrected full steps:

Step1: Match exponents for subtraction

Rewrite $1.969 \times 10^8$ as $19.69 \times 10^7$

Step2: Subtract land from total surface area

$\text{Non-land area} = 19.69 \times 10^7 - 5.761 \times 10^7$

Step3: Factor out common power of 10

$\text{Non-land area} = (19.69 - 5.761) \times 10^7$

Step4: Compute coefficient subtraction

$19.69 - 5.761 = 13.929$

Step5: Convert to proper scientific notation

$13.929 \times 10^7 = 1.3929 \times 10^8$

Answer:

$1.4129 \times 10^8$ square miles