#### Answer

$\approx 11.5$

#### Work Step by Step

The Trigonometric ratios for $sine$ function can be written as follows:
$\ Sin=\dfrac{Opposite}{hypotenuse}$
We are given that the length of hypotenuse and the angle. Our aim is to compute the side of opposite to the angle.
Therefore, $\sin 35^{\circ}=\dfrac{x}{20}$
This implies that $x=20 \sin 35^{\circ} \approx 11.5$