The maths puzzle below looks impossible, but I can assure you it does work. It just depends how much of a mathematian you are. Try working it our for yourself before trying to find any online solutions. It took me ages but I eventually got there.
ABCDE
X
A
EEEEEE
From the figure you get from the above sum work the coordinates out from this:
N51 31.(D-3) (E-2) A W000 36.B (Cx2) B