Applications of Trigonometry Heights and Distances Chapter 9 Exercise 9.1 Question 14
14. A 1.2 m tall girl spots a balloon moving with the wind in a horizontal line at a height of 88.2 m from the ground. The angle of elevation of the balloon from the eyes of the girl at any instant is 60. After some time, the angle of elevation reduces to 30. Find the distance traveled by the balloon during the travel.
Height of balloon from the ground = BG = 88.2 m
We want to find distance traveled by balloon from point A to B.
BC = BG -CG = 88.2-1.2=87 m
AD = BC. Therefore, AD = 87 m
We want to find DC which is equal to AB.
DC = EC - DE m