Lines of latitude on Earth are actually circles. The Tropic of Cancer is the northernmost line of latitude at which the Sun appears directly overhead at noon. The Tropic of Cancer has a radius of 5854 kilometers. To qualify for an around-the-world speed record, a pilot must cover a distance no less than the circumference of the Tropic of Cancer, cross all meridians, and land on the same airfield where he started. A. The minimum distance that a pilot must fly to qualify for an around-the-world speed record is about kilometers. Question 2 b. Estimate the time it would take for a pilot flying at an average speed of 1231 kilometers per hour to fly around the world. At this speed, it would take about hours