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 7 of 11.

Hemanth said:   3 years ago
Why we use the tan formula? Anyone explain me.
(5)

Srikanth said:   1 decade ago
Why you taken Tan and why you not taken cos ?

Ankit said:   1 decade ago
Why you taken Tan and why you not taken cos ?

Mky said:   7 years ago
Why we using only tan why not cot, sin, cos?

Naveen said:   7 years ago
Why should we take tan? Anyone explain me.

Naveen said:   7 years ago
Why should we take tan? Anyone explain me.
(1)

Anudeep said:   4 years ago
Why we are taking √3? Explain please.
(3)

Sumedha said:   1 decade ago
Why we have taken tan and not sin and cos?

Kumar said:   8 years ago
How can you get AB/AC=tan 30*=1/√ 3?

Akhilesh Agrahari said:   9 years ago
By taking 100 common in 100 and 100root3.


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