Aptitude - Height and Distance - Discussion

@All.

Take, Sin or Cos or Tan;

Sin = opposite/hypothesis
Cos = adjacent/hypothesis
Tan = opposite/adjacent.

Given are as following;

The angle is 60 degree.

The foot of leader is 4.6 m away from the wall (CA) this means 4.6m is adjacent,
A leader is leaning on the wall (CB) this will be hypothesis while determining (adjacent opposite or hypothesis but in real sense, it's the length of the leader!
Now, we can make out that it's Cos and not tan or sin because adjacent CA is given (4.6m) while hypothesis CB is x or unknown.

So,
Cos60 = CA/CB.
CB(x) = 4.6/cos60.
x = 9.2.

Thank You.

Here, they asked about the length of the ladder, not about the hypotenuse.

So the correct answer is 7.8m.

Why it will not be 7.8?

Also, we can take tan60,

AB/AC = tan60, =>AB=AC * tan60 =>AB= 4.6*tan60.

In the question, it's given that the foot of the ladder is 4.6m away from the wall. And we could take the given parameter to be either BC or AC. If it is the length of the ladder, then we should use sin and otherwise tan.

In this question, cos indicate is an adjacent side/hypotenuse side.

By using tan you'll end up getting AB which is B the height of the wall but the problem says to find for the length of the ladder then use the value of AB and AC using Pythagorean's theorem c= √(a^2+b^2).

Then BC= √(AB^2 + AC^2) then you"ll get the length of the ladder.

@Chiru.

Yes, you are right and when Tan is taken answer is 7.9.

@All.

Here, it is mentioned that the ladder is leaning on the wall, AB is the wall and BC is the ladder that's the reason we taken Tan.

@All.

Sin=perpendicular. Upon hypotenuse and cos, =base upon hypotenuse and tan=perpendicular upon base. And in this question, we need hypotenuse so cos is applied.

Why can't we solve this using tan?