Aptitude - Height and Distance - Discussion

Discussion Forum : Height and Distance - General Questions (Q.No. 3)
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 2 of 5.

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)

Praveen kumar said:   9 years ago
Great answer Thanks @Rahul Rami.
(1)

Rajan said:   9 years ago
Why can't we use sec instead of cos?
(1)

GAGAN said:   5 years ago
@Anil Kumar.

But they have asked BC not AB. Why are you finding AB?
(1)

Deepali said:   4 years ago
why we take cos here? Explain please.
(1)

Cynthia said:   1 decade ago
Why can't we take in this way:

Tan 60 = AB/4.6.

1.73 = AB/4.6.
AB = 7.958.
(1)

Eben Thomas said:   3 years ago
sin=o/h , cos=a/h, tan=o/a,

Here,
o- Opposite side;
h-Hypotnuse;
a- Adjasent side.
(1)

Jimuta said:   5 years ago
Why it will not be 7.8?

Also, we can take tan60,

AB/AC = tan60, =>AB=AC * tan60 =>AB= 4.6*tan60.

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.


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