1. The problem statement, all variables and given/known data Two points A and B on the surface of the Earth are at the same longitude and 60.0° apart in latitude. Suppose that an earthquake at point A creates a P wave that reaches point B by traveling straight through the body of the Earth at a constant speed of 7.80 km/s. The earthquake also radiates a Rayleigh wave, which travels across the surface of the Earth in an analogous way to a surface wave on water, at 4.50 km/s. What is the time difference between the arrivals of the two waves at B? Take the radius of the Earth to be 6370 km. I have the solution for this but I'm confused as to how to find the distance and the speed in this case. Can someone explain to me step by step as to why he distance is said to be like 2Rsin(30)?