This also simplifies modifying the program, should the value of pi change. Real programmers are surprised when the odometers in their cars don't turn from 99,999 to A0000. C is almost a real language. Even the name sounds like it's gone through an optimizing compiler. Any sufficiently advanced bug is indistinguishable from a feature.
Science is to computer science as hydrodynamics is to plumbing.
We don't really understand it, so we'll give it to the programmers. Computer interfaces and user interfaces are as different as night and 1. A computer scientist is someone who fixes things that aren't broken. The computer is mightier than the pen, the sword, and usually the programmer. Programming is an art form that fights back.