The missing side is x = 4.33
How to find the missing side?
We want to find the missing side in the right triangle. We can see that x is the opposite cathetus of the given angle, so we can use the trigonometric relation:
sin(angle) = (opposite cathetus)/hypotenuse
Replacing what we know, we will get:
sin(18°) = x/14
Solving for x:
x = sin(18°)*14 = 4.33