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 2 of 11.
Kumar said:
4 years ago
For triangle, we use tan mostly. right.
(3)
Uzma said:
1 year ago
Why we are using tan while we have to find the distance?
i.e why tan =1/√3?
i.e why tan =1/√3?
(3)
Bharath said:
5 months ago
We use tan because we know tan is opp by the adjutant.
The opp value is 100 which means the height of the lighthouse, we should know the distance between the two ships so we want the adjacent side.
The opp value is 100 which means the height of the lighthouse, we should know the distance between the two ships so we want the adjacent side.
(3)
Mythili said:
4 years ago
@Yeshi Samdup
How?
CA = 100/tan30,
CA = 173.
Please explain this.
How?
CA = 100/tan30,
CA = 173.
Please explain this.
(2)
Sunitha said:
1 decade ago
How to find out root 3?
(1)
Anish kumar said:
1 decade ago
We can also able to find the answer using sin and cos. But more step is needed.
(1)
Uttam Singh said:
7 years ago
We can use a Divide rule to find the root of any number.
(1)
Naveen said:
7 years ago
Why should we take tan? Anyone explain me.
(1)
Praket Mishra said:
6 years ago
Where we should use sin, cos, tan? Please anyone explain me.
(1)
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)
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