Answer
The value of b to the nearest tenth is $92.9$.
Work Step by Step
By using the sine rule,
$\begin{align}
& \frac{\sin {{12}^{{}^\circ }}}{20}=\frac{\sin {{75}^{{}^\circ }}}{b} \\
& b=\frac{20\times \sin {{75}^{{}^\circ }}}{\sin {{12}^{{}^\circ }}} \\
& b=\frac{20\times 0.96}{0.20} \\
& b\approx 92.8
\end{align}$
Hence, b is approximately $92.9$.
