The figure shows the latitudes of Washington, D. C. and Lima, Peru. The radius of the Earth is approximately 6,370 kilometers. 1. Find the angle at the Earth’s center between radii drawn to Washington and Lima.

2. Find the distance between Washington and Lima. Show your work.

3. A point’s longitude is a measure of its position east or west on the Earth’s surface. In order for your calculation of the distance between Washington and Lima to be accurate, what must be true about the longitudes of the two cities?