Straight-Line Distance on Earth (Chord Length on a Sphere)

This GeoGebra example models Earth as a 3D sphere, drawing the equator, prime meridian, and latitude/longitude grid. It selects two points A and B on the sphere's surface and demonstrates how to calculate the straight-line (chord) distance between them. Using commands like Sphere, Circle, and Sequence to construct the Earth model, it employs Segment and distance formulas to visualize the Euclidean