Now for the second part of the question, this I'm stuck like Ive never been before.

''The shortest distance between Town P (63° N,70° E) and Town Q (y° N, 110° W) is 6702.9km

Determine y° N, the latitude of Q. (The answer is 57° if this helps anyone) I have no clue how to do this.

Here is a picture attached of how I got part (i)

Some useful formulas maybe,

''If you have two places on the same latitude of 24° N, and the angle subtended between them is 120°,(circumference of earth is 40000km)

The shortest distance can be found as follows.

First find circumference of the

parallel of latitude which is c=C*cos(theta)

So: c=*cos24° *40000km =36560km.

SO length of the arc PQ is : l=c*(a/360)

so: l=36560*120/360= 12186.7 km to 1DP.''

Hopefully this example and picture give some insight.

That is just an example. For part (ii) there is a similar way to calculate the latitude, but my book shows only examples where the longitude is the same... and in this case both the latitude and longitude are different.

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