Answer:
19.4 feet
Step-by-step explanation:
When calculating distances using perpendicular angles, we use trig functions such as Sin, Cos, and Tan.
Because our angle and know side value are across from each other and we need to know the hypotenuse, we chose to use Sine.
We set up the equation [tex]sin (68) = \frac{18}{h}[/tex].
We isolate h by multiplying h across the equal sign and dividing sin (68) across as well. [tex]sin (68) = \frac{18}{h}\\hsin (68) = \frac{18}{h}*h\\hsin (68) = 18\\\frac{hsin (68)}{sin (68)} =\frac{18}{sin (68)} \\[/tex]
And finally we have [tex]h=\frac{18}{sin (68)}[/tex]. We input to calculator.
[tex]h=\frac{18}{0.92718} \\h=19.4 feet[/tex]
See the attached picture below showing the shore with the boat out at sea and the position of the person.