Fermi question · Science
About how many kilometers is Earth’s circumference around the equator?
Make a fast, defensible estimate before you reveal the reference answer. Think in factors, not exact recall.
What is your estimate?
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Reference answer
Reveal the reference answer
≈ 40 thousand kilometers
Fermi estimates are judged by scale, so a reasonable approximation can still earn a strong score.
One way to estimate it
Approximate Earth as a sphere and use circumference ≈ 2πr.
- Earth radius≈ 6,371 km
- Circumference formula≈ 2 × 3.14 × radius
- Estimate6.28 × 6,371 ≈ 40,000 km
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