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 6 of 7.

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

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

Shruti jalkote said:   5 years ago
Thanks all.
(1)

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)

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

Gurpreet said:   4 years ago
Thanks all.
(1)

Vivek Sunny said:   4 years ago
@Aditya.

We can choose any ratio either tan or cot.

But, which relates both adjacent and height.

Nicholas Hatontola said:   3 years ago
Why are we considering BC as the length of the shadow instead of AC? Isn't the shadow supposed to be the base?

Please explain me.
(1)

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)


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