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The radius of a circle is so increased that its circumference increased by 5%. The area of the circle, then increases by

A) 12.5%
B) 10.25%
C) 10.5%
D) 11.25%

Correct Answer:


B) 10.25%

Description for Correct answer:

Increase in Circumference of circle = 5%
Increase in radius is also 5%
Now, increase in area of circle
=\( \Large \left(2a+\frac{a^{2}}{100} \right)% \)

where,a=increase in radius

=\( \Large \left(2\times 5+\frac{5\times 5}{100} \right)\% \)=10.25%

Part of solved Area and perimeter questions and answers : >> Elementary Mathematics >> Area and perimeter

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