Aptitude - Height and Distance - Discussion
Discussion Forum : Height and Distance - General Questions (Q.No. 3)
3.
The angle of elevation of a ladder leaning against a wall is 60° and the foot of the ladder is 4.6 m away from the wall. The length of the ladder is:
Answer: Option
Explanation:
Let AB be the wall and BC be the ladder.
Then, 
ACB = 60° and AC = 4.6 m.
| AC | = cos 60° = | 1 |
| BC | 2 |
 BC |
= 2 x AC |
| = (2 x 4.6) m | |
| = 9.2 m. |
Discussion:
45 comments Page 2 of 5.
Lucifer123 said:
10 years ago
@Cynthia.
No wonder girls are dumb.
We want "BC" (the length of the ladder) not "AC" (height of the wall).
No wonder girls are dumb.
We want "BC" (the length of the ladder) not "AC" (height of the wall).
Manjunath said:
10 years ago
They are asking 4.6 m away from the wall. But here its get attach with the wall. How come?
SREEJA said:
9 years ago
How can we remember here we should use "Tan" and there we should use "Cos"?
Rahul RAMI said:
9 years ago
Its very simple @Sreeja.
If we have perpendicular (AB) and say to find hypotenuse (BC) then we use sin Angle.
If we have perpendicular (AB) and say to find Base (AC) then we use tan Angle.
If we have Base (AC) and say to find Hypotenuse (BC) then we use Cos angle.
Note : AB, AC, BC are taken from the solution of this question,
In above example, we have a base (AC) and say to the fine length of ladder means find hypotenuse (BC).
So we can use Cos Angle in this situation.
If we have perpendicular (AB) and say to find hypotenuse (BC) then we use sin Angle.
If we have perpendicular (AB) and say to find Base (AC) then we use tan Angle.
If we have Base (AC) and say to find Hypotenuse (BC) then we use Cos angle.
Note : AB, AC, BC are taken from the solution of this question,
In above example, we have a base (AC) and say to the fine length of ladder means find hypotenuse (BC).
So we can use Cos Angle in this situation.
CatEyes said:
9 years ago
Also according to the position of angle. We decide which one is opposite side and which one is adjacent. So remember the formula for each Sin, Cos, and Tan and solve the problem easily.
Praveen kumar said:
9 years ago
Great answer Thanks @Rahul Rami.
(1)
Rajan said:
9 years ago
Why can't we use sec instead of cos?
(1)
Prasanna kumar said:
8 years ago
Why was the down angle is 60 degrees, angle of elevation means top angle should be top angle should be zero?
(1)
JIT said:
8 years ago
If we take,
tan30=AC/BC,
BC=7.8.
Why can't we solve in this way?
tan30=AC/BC,
BC=7.8.
Why can't we solve in this way?
(1)
Sahil said:
8 years ago
We can do it using tan also.
(1)
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