Question

If the circumference of a circle is increased by 30%. what will be the effect on the area of the circle?

Answer 1

Initial circumference =2Πr

Final circumference = 2Πr +20% of 2Πr

=2Π(1.2r)

So , radius of the new circle so formed ,r' =1.2r

Therefore, area of the new circle = Πr'^2

=1.44Πr^2

=> % increase in area = (Πr^2(1.44–1)/Πr^2 )×100

=44%