Question

If the perimeter of a circle is increased by 20%.what will be the effect on area of circle

Answer 1

Perimeter of circle = 2 pi r units
If 20% is increased means it's Radius increased
New r = (r + r/5) = 6r / 5 unit
Previously area was pi r^2 unit ^2
But now area changes to
[( pi (6r/5)^2]
pi (36r^2/ 25) unit ^2

Ratio between old and new areas
= pi r^2 / pi (36 r^2 / 25)
= 25 / 36