Math, asked by nupursingh44, 10 months ago

a man on the top of a vertical Tower observes a car moving at a uniform speed coming directly towards it if it takes 12 minutes for the angle of depression to change from 30 degree to 45 degree how soon after this will the car reach the tower ​

Answers

Answered by bellaswan30
10

Answer:

hoped this may help you☺

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Answered by RvChaudharY50
1

Solution :-

in Right ∆ABC, we have,

→ tan 45° = AB / BC

→ 1 = AB / BC

→ AB = BC --------- Eqn.(1)

now, in Right ∆ABD , we have,

→ tan 30° = AB / BD

→ (1/√3) = AB / (AB + CD)

→ (1/√3) = AB/(AB + CD)

→ √3AB = AB + CD

→ √3AB - AB = CD

→ AB(√3 - 1) = CD ------------ Eqn.(2)

now, Let us assume that, speed of car is x m/min.

so,

→ Distance covered by car in 12min. = CD

→ Speed * Time = CD

→ 12x = CD

→ x = CD/12 ---------------- Eqn.(3)

therefore,

→ Time taken by car to reach tower = Distance / speed

→ Time = BC / x

putting value of Eqn.(3),

→ Time = 12BC / CD

putting value of Eqn.(2) now,

→ Time = 12BC/AB(√3 - 1)

Putting value of Eqn.(1) now,

→ Time = 12AB / AB(√3 - 1)

→ Time = 12/(√3 - 1)

→ Time = 12/(1.73 - 1)

→ Time = 12/(0.73)

→ Time ≈ 16.4 minutes (Ans.)

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