Half wave sine form factor example
Because you are wrong 

\$ \Large \frac{V_{RMS}}{V_{AVR}} = \frac{\frac{V_{peak}}{\sqrt{2}}}{\frac{V_{peak} }{\pi}}= \frac{V_{peak}}{\sqrt{2}} \cdot\frac{\pi}{V_{peak}} = \frac{\pi}{\sqrt{2}} \approx 2.2214\$

As for the average value in the half wave rectifier:

$$V_{DC} = \frac{1}{2\pi}\int_{0}^{\pi}V_p sin(x) dx = \frac{V_p}{\pi}$$

https://www.symbolab.com/solver/step-by-step/%5Cfrac%7B1%7D%7B2%5Cpi%7D%5Cint_%7B0%7D%5E%7B%5Cpi%7D%20Vp%20sin%5Cleft(x%5Cright)%20dx