The captain drops the 3- foot- long anchor and lets out 100 feet of anchor rope. The boat floats away from where the anchor was dropped until the anchor rope becomes straight due to the tide. The captain uses the yardstick and determines that a total 27 inches of the anchor rope is above the water. Using the inclinometer, the captain determines that the angle of depression of the anchor rope is 42 degrees. The captain knows the water is parallel to the bay floor. ( Elevation and Depression)
Using Trig with the right triangle that is formed by the rope and the water we have a hypotenuse of 27 inches and the angle where the rope leaves the boat of 48 degrees(This is 90 - the depression angle they gave us)
The Cos of 48 degrees = Adjacent/hypotenuse = (distance from p to the water line)/27
So distance from p to the water line= 27(Cos 48) = 18.067 inches or 18 inches to the nearest inch.