Final answer:
By calculating the degrees of Earth's rotation that correspond to a 3-hour time difference and knowing the distance between Miami and Los Angeles, we can estimate Earth's circumference. Although our estimation is not exact because the cities are not on the Equator, the closest given option to our estimation of 24,000 miles is 21,000 miles.
Step-by-step explanation:
To estimate the circumference of the Earth based on the time difference between sunrise in Miami, Florida and Los Angeles, California, we can use the information given that Miami is about 3,000 miles east of Los Angeles and there is approximately a 3-hour difference in sunrise times. Knowing that Earth rotates 360 degrees in 24 hours, we can determine how many degrees correspond to the 3-hour difference:
(3 hours / 24 hours) * 360 degrees = 45 degrees.
Since Miami and Los Angeles are not on the equator, this will underestimate the actual Earth's circumference, but it gives us a starting point. If 45 degrees corresponds to 3,000 miles, then the full 360 degrees would correspond to:
(360 degrees / 45 degrees) * 3,000 miles = 24,000 miles.
However, we're asked to choose the best estimate from the provided options, which are all somewhat smaller than the correct value. As the closest option to our estimate is 21,000 miles, the answer is: d. 21,000 miles.