If Δ is angle of deflection of a simple curve of radius R, the length of the curve is
1
\(\frac{{{\rm{\pi R\Delta }}}}{{90}}\)
2
\(\frac{{{\rm{\pi R\Delta }}}}{{180}}\)
3
\(\frac{{{\rm{\pi R\Delta }}}}{{270}}\)
4
\(\frac{{{\rm{\pi R\Delta }}}}{{360}}\)