Question

the radius of a circle is 3cm what is the circumference of another circle whose area is 49 time of the first

Answer 1

Given Radius of the circle = 3cm.

We know that Area of circle = pir^2.

Given that Area of the circle is 49 times of the first.

pir^2 = 49 * pi * r^2

pir^2 = 49 * pi * (3)^2

r^2 = 441

r = 21cm.


We know that circumference of circle = 2pir

                                                                = 2 * 22/7 * 21

                                                                = 44 * 3

                                                                = 132m^2.


Therefore the circumference of another circle = 132m^2.


Hope this helps!