Aptitude - Height and Distance - Discussion
Discussion Forum : Height and Distance - General Questions (Q.No. 4)
4.
An observer 1.6 m tall is 203 away from a tower. The angle of elevation from his eye to the top of the tower is 30°. The height of the tower is:
Answer: Option
Explanation:
Let AB be the observer and CD be the tower.
Draw BE 
CD.
Then, CE = AB = 1.6 m,
BE = AC = 203 m.
| DE | = tan 30° = | 1 |
| BE | 3 |
 DE = |
203 | m = 20 m. |
| 3 |
CD = CE + DE = (1.6 + 20) m = 21.6 m.
Discussion:
18 comments Page 1 of 2.
Midhun said:
7 years ago
@Akshaya Prasad.
We use tan, sin or cos depending upon what we want to get and what they have given in the question.
For example. If they give opposite side and you want to find the adjacent side. So, we will use a tan.
We use tan, sin or cos depending upon what we want to get and what they have given in the question.
For example. If they give opposite side and you want to find the adjacent side. So, we will use a tan.
Yazhini.M.R said:
1 decade ago
Since tan thetq= opposite/adjacent , tan 30= DE/BE ,
the value of tan 30 is 1/ root 3,
then DE/BE=1/root 3, then DE=BE/root 3,
thus 20 m is obtained.
since CD= CE+DE, 21.6 is obtained.
the value of tan 30 is 1/ root 3,
then DE/BE=1/root 3, then DE=BE/root 3,
thus 20 m is obtained.
since CD= CE+DE, 21.6 is obtained.
Mahksh said:
8 years ago
There is no specific rule for this.
According to the situation we have to find this. Here, in this case, DE/BE i.e. perpendicular upon base means "tan".
So we take tan 30.
According to the situation we have to find this. Here, in this case, DE/BE i.e. perpendicular upon base means "tan".
So we take tan 30.
Jatin007 said:
8 years ago
Applying tan because of we need to find DE.
So tan 30= DE/BE.
tan 30=DE/20√3,
DE=20√3*tan30( value of tan 30=1/√3),
So DE= 20.
So CD= EC+ED=1.6+20=21.6(answer).
So tan 30= DE/BE.
tan 30=DE/20√3,
DE=20√3*tan30( value of tan 30=1/√3),
So DE= 20.
So CD= EC+ED=1.6+20=21.6(answer).
(2)
Vivek Sunny said:
4 years ago
No @Abirami..
cos = adjacent/hypotenuse
tan= opposite/adjacent
For simply, remember...
SOHCAHTOA
where,
s- Sin.
o- Opposite.
h- Hypotenuse.
c- Cos.
t- Tan.
cos = adjacent/hypotenuse
tan= opposite/adjacent
For simply, remember...
SOHCAHTOA
where,
s- Sin.
o- Opposite.
h- Hypotenuse.
c- Cos.
t- Tan.
(1)
Anurag said:
9 years ago
Here DE/BE = 1/root3.
So, DE will be cross multiply by roo3 and BE will be multiplied by 1.
So, how come the value of DE is divided by root 3?
So, DE will be cross multiply by roo3 and BE will be multiplied by 1.
So, how come the value of DE is divided by root 3?
Pooja Kale said:
6 years ago
Remember basic rule,
If Finding :
Perpendicular : Sin
Hypotenuse : cos
Base : tan
If Finding :
Perpendicular : Sin
Hypotenuse : cos
Base : tan
(3)
Abirami said:
5 years ago
Opp/adj is cos not tan.
So, the answer is 31.6.
Thus none of these is the answer.
So, the answer is 31.6.
Thus none of these is the answer.
(3)
Monu_yadav said:
8 years ago
But the unit of 20√3 is not given in a problem. So,answer is None of these.
(1)
Kesavan said:
6 years ago
I'm not getting whether to use tan or cos. Please, anyone, clarify it in detail.
(1)
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers