Study lots else first!!
Stallie's fuel cache being near the pole is where the meridians bunch up close. He needs nav formulae that are accurate over large distances and don't depend too much on tangent of an angle. That gets too large at latitudes near ninety!
In general these days as far as nav is concerned maths is weakly remembered because old-time nav has been supplanted. Given the average pilot's ability to keep track of even his car keys thank the Lord for INS and GPS.
Sometimes it is handy to know a bit about equal time points or where we will cross say a line of latitude or longitude. If we did plane trigonometry at school then fine, you only have a little more to learn. If you didn't then I told you education is going to the dogs, Mother!
Spherical trigonometry... ellipses. hyperbolae, circles and triangles as laid out on the spherical earth is the stuff of the chartmaker. And us if we don't want to faff about with large swatches of paper yet need to know something at the planning stage. Like stallie and his cache.
On a sphere the sides of a triangle become curved and the sum of the interior angles is no longer 180 degrees as it was on the plane blackboard of the schoolroom. But the trig formulae are familiar, usually with only one extra term added to account for curvature.
The real life globe is a sphere somewhat flattened at the poles. So really accurate calculations are a little tougher on a flattened spheroid.
Some work of course you can do off a paper chart. In the RAAF/RAF some charts even have a false equator because some math formulae don't work well near the poles (tangent of an angle being one) but if you are happy to accept the world as a sphere you can put the ruddy equator where you like as far as spatial nav is concerned. Just remember where you put it.
Given how easy a spreadsheet is or an applet, compared to slogging away with paper and pencil many things are solvable in seconds. I'd download compsys21 and keep it handy for future work but don't let stuff get between yourself and the prime objective.
Enjoy! I flew for 16000 hours and never hit anything I wasn't supposed to!!
The "E"