Answer
$
4.2^\circ F
$; approximately equal to the temperature on the given table
Work Step by Step
Using the given formula, $
\text{Windchill}=35.74+0.6215T-35.75V^{4/25}+0.4275TV^{4/25}
$, with $T=20$ and $v=20$, then
\begin{align*}
\text{Windchill}&=35.74+0.6215(20)-35.75(20)^{4/25}+0.4275(20)(20)^{4/25}
\\&\approx
4.2
.\end{align*}
Hence, the windchill temperature is approximately $
4.2^\circ F
$. This temperature is approximately equal to the temperature on the $4$th row, $3$rd column (equal to $
4
$) of the given table.