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?

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

To answer both parts of your question, we need to consider the properties of the Earth's coordinate system, which is based on longitude and latitude.

(a) The longitude specifies an east-west position on the Earth's surface. It ranges from -180 degrees (west) to 180 degrees (east), with 0 degrees at the Prime Meridian (which passes through Greenwich, London).

Since x and y are points on opposite ends of a diameter through the center of the Earth, they are 180 degrees apart in terms of longitude. If the longitude of x is 19 degrees East, we can determine the longitude of y by subtracting 19 degrees from 180 degrees:

Longitude of y = 180 degrees - 19 degrees = 161 degrees East

Therefore, the longitude of y is 161 degrees East.

(b) The latitude specifies a north-south position on the Earth's surface. It ranges from -90 degrees (south) to 90 degrees (north), with 0 degrees at the Equator.

Since x and y are on opposite ends of a diameter, they will have the same latitude but with opposite signs. If the latitude of x is 52 degrees North, the latitude of y will be 52 degrees South.

Therefore, the latitude of y is 52 degrees South.