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:
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.
Viraj said:
8 years ago
How to find √3?
(1)
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.
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.
Please correct me, if I am wrong.
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?
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?
Puneet kulkarni said:
7 years ago
We have formula:
Tan=perpendicular/base
Sine=perpendicular/hypothesis
Cos=base/hypothesis.
Tan=perpendicular/base
Sine=perpendicular/hypothesis
Cos=base/hypothesis.
Neeraj said:
7 years ago
Why can't we solve this using tan?
Bhavy said:
7 years ago
@All.
Sin=perpendicular. Upon hypotenuse and cos, =base upon hypotenuse and tan=perpendicular upon base. And in this question, we need hypotenuse so cos is applied.
Sin=perpendicular. Upon hypotenuse and cos, =base upon hypotenuse and tan=perpendicular upon base. And in this question, we need hypotenuse so cos is applied.
Chiru said:
6 years ago
@All.
Here, it is mentioned that the ladder is leaning on the wall, AB is the wall and BC is the ladder that's the reason we taken Tan.
Here, it is mentioned that the ladder is leaning on the wall, AB is the wall and BC is the ladder that's the reason we taken Tan.
Brinda said:
6 years ago
@Chiru.
Yes, you are right and when Tan is taken answer is 7.9.
Yes, you are right and when Tan is taken answer is 7.9.
Niezel said:
6 years ago
By using tan you'll end up getting AB which is B the height of the wall but the problem says to find for the length of the ladder then use the value of AB and AC using Pythagorean's theorem c= √(a^2+b^2).
Then BC= √(AB^2 + AC^2) then you"ll get the length of the ladder.
Then BC= √(AB^2 + AC^2) then you"ll get the length of the ladder.
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