A helicopter flying directly over a fishing boat at an altit

A helicopter, flying directly over a fishing boat at an altitude of 1200 ft, spots an ocean liner at a 15degreeangle of depression. How far from the boat is the liner? Round to the nearest foot.

Solution

Given figure is a right angled triangle: with height = 1200 feet

Angle = 15 deg ; Base of triangle is the distance between the boat and liner be it x

So, tan15 = 1200/x

x= 1200/tan15 = 4478.46 feet