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:
173 m
200 m
273 m
300 m
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 4 of 11.

Kanishka Roy said:   5 years ago
How do you decide which is the base and which is the height? Explain it, please.

Anish kumar said:   1 decade ago
We can also able to find the answer using sin and cos. But more step is needed.
(1)

Kishor said:   7 years ago
How? tan 45° = 1
AD = AB = 100 m. How it is? Explain in detail.

Uzma said:   1 year ago
Why we are using tan while we have to find the distance?

i.e why tan =1/√3?
(3)

Swapnil said:   8 years ago
How to find root3 value, please explain in detail. How to come 1.732?

Mythili said:   4 years ago
@Yeshi Samdup

How?

CA = 100/tan30,
CA = 173.

Please explain this.
(2)

Kavya sreeram said:   9 years ago
Tan 30 is 1/√3 right? then in all problem, it is 1, how come?

Jowy said:   1 decade ago
The tan30 is root(3) divide by 3. So how did you get root(3) ?

Prasad said:   1 decade ago
How to solve the problem I am not under standing for Tan value.

Ram said:   9 years ago
I do not understand. Please, anyone, give a simple explanation.


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