Great and small circle distances, the spherical cosine rule, longitude and time, UTC, the date line and travel problems

What this note covers

1. Use angular separation on a great circle
2. Calculate distance along a small circle
3. Find general great-circle separation
4. Convert longitude and standard time through UTC
5. Handle the date line and travel duration
6. Audit an Earth-geometry or time solution

6 sections · 10 key terms & formulas · 6 common mistakes