Question

If the area of circle increases by 36.96 cm square when it's radius is increased by 1.4 cm, then find the original radius of the circle​

Answer 1

π{(1.4r)^2-(r)^2}=36.96

πr^2(1.96-1) =36.96

πr^2×0.96=36.96

πr^2=38.5

r^2=12.25

r=3.5

original radius=3.5cm