Mohit is standing at some distance from a 60 meters tall building. Mohit is 1.8 meters tall. When Mohit walks towards the building, then the angle of elevation from his head becomes 60° from 45°. How much distance (in metres) Mohit covered towards the building?
Mohit is standing at some distance from a 60 meters tall building. Mohit is 1.8 meters tall. When Mohit walks towards the building, then the angle of elevation from his head becomes 60° from 45°. How much distance (in metres) Mohit covered towards the building? Correct Answer 19.4 (3 - √3)
Given :
Mohit is 1.8 m tall and standing at some distance from 60 m high building
Calculations :
We can use the following table for the values of trigonometric functions at specific values of angle θ:
[ alt="Trigo - Angles and Radian" src="//storage.googleapis.com/tb-img/production/21/02/Trigo%20-%20Angles%20and%20Radian.PNG" style="width: 392px; height: 218px;">
[ alt="F1 Ashish Singh Anil 24.02.21 D30" src="//storage.googleapis.com/tb-img/production/21/02/F1_Ashish%20Singh_Anil_24.02.21_D30.png" style="width: 314px; height: 218px;">
According to the question
Height of Mohit(CF) = 1.8 m
Now ∆ABC
tan45° = AB/BC
⇒ BC = AB
⇒ BC = 58.2 m
In ∆ABL
tan60° = AB/BL
⇒ BL = AB/√3
⇒ BL = 19.4√3
Distance(LC) covered by Mohit = BC - BL
⇒ 58.2 - 19.4√3
⇒ 19.4(3 - √3) m
∴ Total distance covered by Mohit is 19.4(3 - √3) m