How the Mathematical Ninja approximates $\sin(55º)$ | Colin

“$0.819$,” said the Mathematical Ninja, in as weary a voice as the student used to say “I suppose you’re going to tell me how.”

The nunchaku looked a little rusty, and the axe was in need of a good sharpening. The throwing knives could have done with a clear, and the broadsword… well, once upon a time, it would have been a point of pride to have not a spot of blood on it.

“Interpolation!” said the Mathematical Ninja, a little bit glumly. Christmas was coming, and Christmas meant having to hang out with the Ninja family rather than do Ninja maths.

“Go on…” said the student.

“Well,…