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Aptitude - Height and Distance - Discussion

Discussion Forum : Height and Distance - General Questions (Q.No. 1)
Height and Distance
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 6 of 11.
Sehdev said:   8 years ago
How we calculated the square root of 3 that we got 1.73?
Sathish said:   8 years ago
Why we use tan instead of cos, sin please explain?
Jeni said:   8 years ago
How the value of AD is said to be 100?, It is not given question, but it is said to be 100? why?
Sathish said:   8 years ago
Why we have use tan?
Kumar said:   8 years ago
How can you get AB/AC=tan 30*=1/√ 3?
Swapnil said:   8 years ago
How to find root3 value, please explain in detail. How to come 1.732?
Preetam said:   8 years ago
We have taken tan. Instead of sin or cos because perpendicular is given and we need to find the base, so tan is equal to perpendicular/base. So for that, we need a tan.
Amol meher said:   8 years ago
Why are uesd tan? Please explain me.
Gaurav Radheshyam Jaiswal said:   8 years ago
Why are used tan only?
Masthan shaik said:   8 years ago
√3 means the square of 3.

It calculated as 1.732. Because two same numbers give their square root.
i;e 2 * 2 = 4,3 * 3 = 9 just like this 1.732 * 1.732 = 2.999824 it is nearest to 3 then 1.732 is square root of 3.
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