Final answer:
The coastal city of Raphia is approximately located at 31°N latitude, 34°E longitude, near modern-day Rafah at the Egypt-Gaza border.
Step-by-step explanation:
The location of the coastal city of Raphia is approximately 31°N latitude, 34°E longitude. This estimation is based on the historical location of Raphia, near modern-day Rafah at the border of Egypt and the Gaza Strip. When considering the question about Alexandria's latitude, it's important to note that Alexandria is situated close to 31°N latitude, 30°E longitude.
The information provided in the question references the calculation of Earth's circumference using Eratosthenes's method, which highlights how the difference in sunlight angle at two different latitudes can be used to determine the Earth's size. While the historical question may not directly relate to Raphia, understanding Eratosthenes's use of latitude for calculation can be useful for locating places on Earth.