Question

U.S. national forests cover approximately 300,000^2 square miles. Conservationists want the total square footage of forests to be 300,000^2 square miles. When Ivanna used her phone to do the calculation, her screen showed the following: 9e+10. What does the answer on her screen mean? Explain how you know.

a) The answer on her screen means 9 x 10^10 square miles.
b) The answer on her screen means 90,000,000,000 square miles.
c) The answer on her screen means 9,000,000,000,000 square miles.
d) The answer on her screen means 9,000 square miles.

Answer 1

The answer on Ivanna's screen, 9e+10, means 9 times 10 to the 10th power, which expands to 90,000,000,000 square miles, indicating that option (b) is correct.

Step-by-step explanation:

The answer on Ivanna's screen, 9e+10, is a notation used in scientific calculators and computers to represent large numbers efficiently.

This notation is known as scientific notation, and it is used to express numbers that are too large or too small to be conveniently written in decimal form. In scientific notation, 9e+10 means 9 times 10 to the 10th power (9 x 1010). When expanded, this equals 90,000,000,000 square miles.

This is because the exponent, +10, signifies the number of times the base of 10 is multiplied by itself, and then this product is multiplied by 9. Therefore, the correct answer is option (b), which corresponds to 90 billion square miles.