Question

The radius of a circle is so increased that it's circumference increased by 5% find the percentage ncreased in its area

Answer 1

Increase in Circumference of circle = 5%
Increase in radius is also 5%
Now, increase in area of circle
=(2a+a2100)(2a+a2100)

where,a=increase in radius

=(2×5+5×5100)%
(2×5+5×5100)%
=10.25%