Here’s a useful observation: The Golden Ratio is roughly the same as the ratio between miles and kilometers. As successive terms in the Fibonacci sequence approximate the Golden Ratio, the sequence comes in handy for quick conversions.
Here are the first 20 terms:
| F0 | F1 | F2 | F3 | F4 | F5 | F6 | F7 | F8 | F9 | F10 | F11 | F12 | F13 | F14 | F15 | F16 | F17 | F18 | F19 | F20 |
| 0 | 1 | 1 | 2 | 3 | 5 | 8 | 13 | 21 | 34 | 55 | 89 | 144 | 233 | 377 | 610 | 987 | 1597 | 2584 | 4181 | 6765 |
Using the Fibonacci, we approximate 987 miles (F16) as 1597 km. Google’s conversion tells us that 987 miles equals 1,588 km.
Not bad, eh?