text: Geometry: Common Core (15th Edition)
  
  $x = 34.2$ ft.
  Since we have the measure of one angle and the measure of the hypotenuse, we can use the sine ratio to find $x$, which is the side opposite to the angle. The sine ratio is given as follows: sin $A = \frac{opposite}{hypotenuse}$ Let's plug in what we know: sin $20^{\circ} = \frac{x}{100}$ Multiply each side by $100$: sin $20^{\circ}(100) = x$ Multiply to solve: $x = 34.2$ ft.