Fermi question · Geography
About how many kilometers long is the Grand Canyon along the Colorado River?
Make a fast, defensible estimate before you reveal the reference answer. Think in factors, not exact recall.
What is your estimate?
Your result will appear here after you submit a guess.
Reference answer
Reveal the reference answer
≈ 446 kilometers
Fermi estimates are judged by scale, so a reasonable approximation can still earn a strong score.
One way to estimate it
Start from the commonly cited 277 river miles and convert to kilometers.
- River length≈ 277 miles
- Kilometers per mile≈ 1.6
- Estimate277 × 1.6 ≈ 443 km
Keep practicing
Try another question, or return to the daily challenge to build your personal sense of scale.