x and y are points on the earth's surface at opposite ends of a diameter through the centre of the Earth. (a) If the longitude of x is 19 degrees East, what is the longitude of y? (b) If the latitude of x is 52 degrees North, what is the latitude of y?

Answer 1

if one end of a diameter has (a,b) as its latitude and longitude, then the other end has coordinates (-a,b±180°) where + is N or E, and - is S or W