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Aptitude - Height and Distance - Discussion

Discussion Forum : Height and Distance - General Questions (Q.No. 3)
Height and Distance
3.
The angle of elevation of a ladder leaning against a wall is 60° and the foot of the ladder is 4.6 m away from the wall. The length of the ladder is:
2.3 m
4.6 m
7.8 m
9.2 m
Answer: Option
Explanation:

Let AB be the wall and BC be the ladder.

Then, ACB = 60° and AC = 4.6 m.

AC = cos 60° = 1
BC 2

BC = 2 x AC
= (2 x 4.6) m
= 9.2 m.

Discussion:
45 comments Page 3 of 5.
Puneet kulkarni said:   7 years ago
We have formula:

Tan=perpendicular/base
Sine=perpendicular/hypothesis
Cos=base/hypothesis.
Gaurav said:   7 years ago
@Nikita.

How these combinations of base and perpendicular, hypotenuse and perpendicular, hypotenuse and base and so on are formed?

Just tell where is the rule that cos will be equal to Base/Perpendicular rather than Base/Hypotenuse?
Prasad Chachadi said:   7 years ago
Here, the elevation with respect to the wall but in the solution, it is taken with respect to the land!

Please correct me, if I am wrong.
Priya said:   7 years ago
Because of cos = adjacent/hypotenuse if we take tan it becomes AB/AC we need a length of the ladder ie BC so we take cos, ie AC/BC.
Viraj said:   8 years ago
How to find √3?
(1)
Sahil said:   8 years ago
We can do it using tan also.
(1)
JIT said:   8 years ago
If we take,

tan30=AC/BC,
BC=7.8.

Why can't we solve in this way?
(1)
Prasanna kumar said:   8 years ago
Why was the down angle is 60 degrees, angle of elevation means top angle should be top angle should be zero?
(1)
Rajan said:   9 years ago
Why can't we use sec instead of cos?
(1)
Praveen kumar said:   9 years ago
Great answer Thanks @Rahul Rami.
(1)
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