The metric system does use grads? I've come across them quite often in my line of work...
Indeed. Which is why the nautical mile to kilometre ratio is so neatly close to 100/54. In the same way that the nm is a minute of arc, the km is a centigrad of arc.
There are 90 x 60 nautical miles between the equator and the pole.
There are 100 x 100 kilometres between the equator and the pole.
The real fault here lies with evolution for cursing us with 2 fewer fingers than would be mathematically neat.
