4. Columbus had a hard time convincing anyone to undertake the expense of financing a voyage to an unknown place. Based on the information available from other sailors and partly on his own ideas, Columbus underestimated the circumference of the Earth by twenty-one percent. The circumference of the Earth is 24,901 miles at the Equator. What was Columbus' estimate of the Earth's circumference? Round your answer to the nearest mile.
0.79 * 24901 = ?
19,671.79
Yes. Rounded it's 19,672 miles.
To determine Columbus' estimate of the Earth's circumference, we need to calculate what twenty-one percent of the actual circumference is and then subtract it from the actual circumference.
Step 1: Calculate twenty-one percent of the actual circumference.
21% of 24,901 miles = (21/100) * 24,901 miles ≈ 5,229.21 miles
Step 2: Subtract the calculated value from the actual circumference.
Estimated circumference = 24,901 miles - 5,229.21 miles ≈ 19,671.79 miles
Therefore, Columbus' estimate of the Earth's circumference was approximately 19,672 miles (rounded to the nearest mile).