Aptitude - Height and Distance - Discussion

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"Success has many fathers, while failure is an orphan."

- (Proverb)

The angle of elevation of a ladder leaning against a wall is 60º and the foot of the ladder is 4.6 m away from the wall. The length of the ladder is:

[A].	2.3 m	[B].	4.6 m
[C].	7.8 m	[D].	9.2 m

Answer: Option D

Explanation:

Let AB be the wall and BC be the ladder.

Then, ACB = 60º and AC = 4.6 m.

AC = cos 60º = 1

BC 2

BC = 2 x AC

= (2 x 4.6) m

= 9.2 m.

Shyam said: (Sat, Mar 26, 2011 06:03:25 AM)

Why the above two problem we taking "tan", but for this problem we took "cos". Anyone explain ?

Nikita said: (Wed, Aug 10, 2011 04:30:22 PM)

Shyam and Asish, Absolutely we can take tan. but if we take tan we will get AB. Then we have to take sin to find length of the ladder, i.e BC. It 'll take more time..so only we take cos in this problem.