Meme of two women fighting while a man smokes from a pipe in the background.
The women fighting are labeled "mathematicians defining pi" and "engineers just using 3 because it's within tolerance"
The man smoking is labeled "astrophysicists" and the pipe is labeled "pi = 1"
I just use the pi from my calculator or numpy/matlab. But I'm often too lazy for vacuum speed of light and use 3e8 m/s.
That's close enough for radio. You can't cut an antenna much closer than that precision, and it'll stretch or shrink with temperature anyway. I guess the error could add up enough to be a problem in lengths of fibre optic cables, especially as they run at about c/3
That's kind of the beauty here, you only get a relative error (0.069%) and it's mostly insignificant to the point of being smaller than your fabrication tolerances. This should also be the case for fibre optics. The error can't really add up, you scale everything to a multiple of the wavelength and you calculate the wavelength using the speed of light.