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.

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)

Kapil said:   1 decade ago
Angle ACB = Angle BCA
There are different ways to do same question.

they are using cot @ =AC/BC

but you can also use tan @ = perpendicular/base = AB/AC

Balaji said:   1 decade ago
Let me explain here, here carefully,

Here in the problem tree is taken as perpendicular i.e. AB and they also informed that the shadow of tree 3 times the tree i.e. 3 AB. Here shadow is nothing but base.

So we have formula that cot thita = cos θ/ sin θ

Cot θ= AC/AB
= 3 * AB/AB
Cot θ= 3
Cot θ= Cot 30

θ = 30

Appu said:   1 decade ago
Thank you Balaji.

Anchal said:   1 decade ago
We can also solve like this...let AB=x, then AC=3x, Now
AB/AC=tanθ
then x/3=tanθ

After crossing x from x..we get
1/3=tanθ
so tan 30=1/3
so θ=30...Ans..

Kanaga said:   1 decade ago
Hi,

I am not getting the question correctly. They have asked about the angle of elevation of sun. Why should we go for angle of elevation of tree?

Baribie said:   1 decade ago
Can any one explain the question?

Mjp said:   1 decade ago
The sun forms a angle of depression. So as the sun is very far away it is hard to take the value, so we can take the angle of elevation of a tree which is equal to the angle of depression.

Kanaga said:   1 decade ago
@Mjp:Thanks!!!

Shro said:   1 decade ago
Thanks Balaji


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