Civil Engineering - UPSC Civil Service Exam Questions - Discussion

37. 

A circle of radius 7 m has a standard error of 0.02 m on the radius. The standard error of its area is

[A]. 0.04 m2
[B]. 0.14 m2
[C]. 0.28 m2
[D]. 0.88 m2

Answer: Option C

Explanation:

No answer description available for this question.

Sourav Changdar said: (Sep 29, 2017)  
How to solve this?

Diptayandas said: (Dec 1, 2017)  
Ans will be 0.88m^2.

Ea=0.02*2*π*7.

Sadashiva said: (Aug 26, 2018)  
A= πr^2.

dA/dr=2πr,
eA=er*dA/dr,
=. 0.02*2*r,
=. 0.02*2π*7,
=. 0.88 m^2.

So option D is correct.

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