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 11 of 11.

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

Sam said:   1 decade ago
Just remember root3=1.73 and root2=1.41

we take ab/ac because we want to find ac and we only know ab thats it

Ravi said:   1 decade ago
Why we take AB/AC, AB/AD?

Sunitha said:   1 decade ago
How to find out root 3?
(1)


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