ATPL Navigation Practice Questions - Airline Transport Pilot Licence Navigation Exam

The Earth is an oblate spheroid; the polar radius is approximately 21.5 NM (0.3%) shorter than the equatorial radius. The Earth is a prolate spheroid; the polar radius is approximately 21.5 NM (0.3%) longer than the equatorial radius. The Earth is a perfect sphere; the polar and equatorial radii are exactly equal to 3,440 NM. The Earth is an oblate spheroid; the polar radius is approximately 80 NM (1.2%) shorter than the equatorial radius.