guys help pls

The diagram shows the flight path of a satellite around the earth.

A program is needed to calculate the distance between points A and B shown on the diagram. The program should assume that the flight path is circular and points A and B are in the same distance apart in both directions along the flight path.

The program should do the following:
Ask the user for the straight line distance in miles between points A and B
Convert the value to kilometres
Calculate the distance from point A to point B along the flight path
Output the distance (to the nearest kilometre) to the user