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.
Jambay said:
5 years ago
How come √3 + 1?
(1)
Velraj vj.k said:
5 years ago
How to find √3? Please explain.
Prasad said:
6 years ago
@All.
Know, how we get the 'tan'.
In the question is given we have to find the distance then that time we are not treating the angle of elevation so we have to take distance and hight then the formula becomes;
Tan=opp/adj.
Then AB/AC look at the figure it will be clear for you.
Know, how we get the 'tan'.
In the question is given we have to find the distance then that time we are not treating the angle of elevation so we have to take distance and hight then the formula becomes;
Tan=opp/adj.
Then AB/AC look at the figure it will be clear for you.
(1)
Praket Mishra said:
6 years ago
Where we should use sin, cos, tan? Please anyone explain me.
(1)
Gopi said:
6 years ago
Why should you took tan angle why not take sin angle?
Likitha said:
6 years ago
Thanks all for explaining clearly.
Mrinayak said:
6 years ago
How to find the √3 value? Please explain the process.
Divakar said:
6 years ago
What is the reason to take tan? Please tell me.
Kowsalyadevi said:
6 years ago
First, understand the problem from the given Diagram.
We have to find the distance of the CD.
So, first identify how to use 45° and 35°.
Only by using tan because we know AB value
We know that tanx = perpendicular/base.
tan 30° = AB/CA.
1/√3= 100/CA.
CA=100 x √3.
tan 45° = AB/AD.
1 = 100/AD,
AD = 100.
We know that CD = CA+CD.
= 100x√ 3+100,
= 100(√3+1),
= 100(1.73+1),
= 100(2.73),
= 273m.
We have to find the distance of the CD.
So, first identify how to use 45° and 35°.
Only by using tan because we know AB value
We know that tanx = perpendicular/base.
tan 30° = AB/CA.
1/√3= 100/CA.
CA=100 x √3.
tan 45° = AB/AD.
1 = 100/AD,
AD = 100.
We know that CD = CA+CD.
= 100x√ 3+100,
= 100(√3+1),
= 100(1.73+1),
= 100(2.73),
= 273m.
Kishor said:
7 years ago
How? tan 45° = 1
AD = AB = 100 m. How it is? Explain in detail.
AD = AB = 100 m. How it is? Explain in detail.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers