Take the tour ×  This question already has an answer here:  I
have two related questions:  1- Why do we have 360 degrees in a
circle?  2- I have seen in most of the mathematical concepts,
angle is expressed in radians not in degrees. Why was radian
introduced?  share|improve this question A good place to start
is Wikipedia: en.wikipedia.org/wiki/Degree_(angle),
en.wikipedia.org/wiki/Radian. –  Jonas Meyer Jan 31 at 6:48 We
don't need radians. But if we insist on using degrees, many
important formulas, particularly in any field that uses
calculus, get more complicated, In the same way, we don't need
the usual metric system, we could use inches, feet, yards,
furlongs, miles. But that is far messier. –  André Nicolas Jan
31 at 6:50 add comment  marked as duplicate by Ｊ. Ｍ., Amzoti,
O.L., Lord_Farin, Henry T. Horton Jun 7 at 17:59   3 Answers
Possibly the most important reason for using radians instead of
degrees to measure angles is that it's the simplest way for
computing the straight length subtended by a cir