Saloni Tandon
Saloni Tandon
9 years ago

It circumference of a circle is decreased by 50%, find the percentage decrease in its area.

A. 50%

B. 55%

C. 65%

D. 75%

E. None of these

Solution(By Examveda Team)

Cercumference of the circle is given by, 2* Pi * R.

Where 2 and value of Pi is constant. It means cercumference decreaases 50% only due to 50% decrease in radius.

Let original radius = R.

Original circle area = Pi * R*R = 3.14 *R *R.

Second radius = R/2.

Area = Pi * R/2 * R/2 = (3.14 *R *R)/4
Difference in area = 3.14 *R *R. - (3.14 *R *R)/4. = 2.35 *R *R

% change in area =[ ( 2.35 *R *R) *(100)] / (3.14 *R *R.) = 75%.

 


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