Question

find the circumference of a circle whose area 20 times .the area of a circle of circumference 144 cm?

Answer 1

circumference 2πr=144
                            r=144/2π
                      area=πr²=π×20736/4π²=20736/4π
area of circle which is 20 times area of this circle=20736/4π×20=414720/4π
πr²=414720/4π
r²=414720/4π²
r=√414720/4π²
r=643.98/4π²

Answer 2

Sol) Circumference=2πr
                               =2 x 3.14 x 144
                               =6.28 x 144
                               =904.32
       So the Circumference of the circle is 904.32.