Aptitude - Height and Distance - Discussion
Discussion Forum : Height and Distance - General Questions (Q.No. 1)
1.
Two ships are sailing in the sea on the two sides of a lighthouse. The angle of elevation of the top of the lighthouse is observed from the ships are 30° and 45° respectively. If the lighthouse is 100 m high, the distance between the two ships is:
Answer: Option
Explanation:
Let AB be the lighthouse and C and D be the positions of the ships.
Then, AB = 100 m, 
ACB = 30° and ADB = 45°.
| AB | = tan 30° = | 1 |  AC = AB x 3 = 1003 m. |
| AC | 3 |
| AB | = tan 45° = 1 AD = AB = 100 m. |
| AD |
 CD = (AC + AD) |
= (1003 + 100) m |
| = 100(3 + 1) | |
| = (100 x 2.73) m | |
| = 273 m. |
Discussion:
104 comments Page 3 of 11.
Sumedha said:
1 decade ago
Why we have taken tan and not sin and cos?
Manisha said:
1 decade ago
Why we taken only tan? please explain.
Srinureddy said:
1 decade ago
Hello friends. As best of my knowledge. Here we find the distance between two ships i.e. (AC+AD).
Here we know the height of the lighthouse (AB=100m). For the sake of we taken only (TAN = AB/AC). But not take. Sin&Cos.
Here we know the height of the lighthouse (AB=100m). For the sake of we taken only (TAN = AB/AC). But not take. Sin&Cos.
Prasad said:
1 decade ago
How to solve the problem I am not under standing for Tan value.
Vijeth said:
10 years ago
Why you multiply 3?
Bhanu said:
10 years ago
Section A of 5th standard has a class strength of 40 with an average height of 100.5 cm. Section B has a class.
Strength of 50 with an average height of 96 cm. What is the weighted average height of students in the 5th.
Standard? (Rounded to the nearest 0.5 cm).
Strength of 50 with an average height of 96 cm. What is the weighted average height of students in the 5th.
Standard? (Rounded to the nearest 0.5 cm).
Ganesh said:
10 years ago
Just try to understand.
We need to find AC and we know only AB.
BY P. Theorem, perpendicular/base, i.e.. AB/AC i.e., = tan.
1) We didn't know the value CB, if we take AB/CB no AC omit this.
2) AC/CB both value not known so no chance.
3) There is nothing called AC/AB mean base/perpendicular cancel this.
That's it try to read formula section you will understand.
We need to find AC and we know only AB.
BY P. Theorem, perpendicular/base, i.e.. AB/AC i.e., = tan.
1) We didn't know the value CB, if we take AB/CB no AC omit this.
2) AC/CB both value not known so no chance.
3) There is nothing called AC/AB mean base/perpendicular cancel this.
That's it try to read formula section you will understand.
Siddhant Acharya said:
10 years ago
It has been asked the distance between the two ships not the distance between the peak of the lighthouse and the ship. The one which has an elevation of 30 degrees will have a different value rather than (100 root 3).
Anjum shaikh said:
10 years ago
Can you give me trigonometry formula which are use to solve height and length of problem?
How can we solve problem in less time logically?
How can we solve problem in less time logically?
DINESH RANA said:
10 years ago
Simply we can easily solve the problem.
We can use the trigonometric formula:
As we know that:
(1) sinx = perpendicular/hypotenuse.
(2) cosx = base/hypotenuse and third one is a.
(3) tanx = perpendicular/base.
We can use the trigonometric formula:
As we know that:
(1) sinx = perpendicular/hypotenuse.
(2) cosx = base/hypotenuse and third one is a.
(3) tanx = perpendicular/base.
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