Question

You've dropped your car keys at night off the end of a dock into water 1.6 m deep. a flashlight held directly above the dock edge and 0.50 m above the water illuminates the keys when it's pointed at 40° to the vertical. what is the horizontal distance x from the edge of the dock to the keys

Answer 1

The total height from flash light to the keys is 1.6 + 0.5 = 2.1 meters

the vertical angle = 40 degrees

the horizontal distance =  2.1 x tan(40)

distance = 1.76 meters  ( round answer as needed )