Aptitude - Height and Distance - Discussion

Discussion Forum : Height and Distance - General Questions (Q.No. 6)
6.
The angle of elevation of the sun, when the length of the shadow of a tree 3 times the height of the tree, is:
30°
45°
60°
90°
Answer: Option
Explanation:

Let AB be the tree and AC be its shadow.

Let ACB = .

Then, AC = 3         cot = 3
AB

= 30°.

Discussion:
62 comments Page 1 of 7.

Shaik Nayab said:   3 years ago
Consider <ABC,

Height of the tree taken as = h.
Given, length of the shadow of a tree √3 times the height of the tree = √3 h.
I have taken, tan θ = BC/AC.
= h/√3 h.
=> numerator and denominator " h" canceled;

Remaining = 1/√3.
So, tan θ = 1 /√3 (Given data on both sides, opposite and adjacent sides, so I can take tan).

Then, θ = 30°.
(13)

Jabbar jr said:   2 years ago
The length of the shadow fo the tree is √3.
Here we want length of the tree only, So;
tanθ=opp/adj.
tanθ = x/√3.
θ=x/√3 => θ=1/√3.
So, the answer is θ = 30°.
(12)

Ravi said:   5 years ago
Here we solve the problem by using the angle of depression. Let β the angle of depression made by the sun on the tree.

Then angle β is equal to the angle of BCA.

Given the length of shadow is √3 times the height of tree i.e., AC=√3AB.

tanβ = AB/AC = AB/√3AB = 1/√3

tanβ = tan30° =>β = 30°.
(3)

Aditya said:   5 years ago
Why cot is taken here. Why we cannot take tan? Please explain me.
(2)

Aditi said:   5 years ago
Here we are taking base AC as a shadow of height then we can solve it like;

Given-
Shadow of a tree is √3 times the height of the tree.

Height = √3AB.
3AB/AC.
3 = AC/AB.
tan = 1/cot.
tan = Perpendicular/Base so the inverse of tan is cot.
Cot = AC/AB (Base/Perpendicular).
Cot 3 = 30°.
(2)

Siddharth said:   3 weeks ago
The length of the tree = AB, shadow of tree = CB.
Assume AB = x then CB = √3x.
Now , tanθ = AB / CB = x/√3x = 1/√3.
we know tan30° = 1/√3.
So, θ = 30°
(1)

Idiotshere said:   1 decade ago
Help me please!.

I'm not getting here why we are saying ACB why don't BCA ?

And another is that why AC/AB why don't AB/AC = tan60 ?
(1)

Aravind said:   6 years ago
AB/AC=1/√3.
TANθ=30θ.
(1)

Lory said:   5 years ago
I can't understand the question yet.
(1)

Vaibhav said:   5 years ago
Thank you all for explaining.
(1)


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