Recalling high school maths from a very long time ago, I remembered that you could project points around the outside of a circle. What took some looking up (because I didn't remember this piece, was that the angle used had to be in radians.
First step was to divide 360 by 16 to get the degrees. So first degree used was 22.5. Add 22.5 for each consecutive angle, which gets you to 360 around the circle.
Convert these angles to radians.
Then it becomes a simple cosine for the longitude and sine for the latitude
A few joins later and create line formula, and you get the answer.