Question

The area of a circle is 400 times the another circle. what is the ratio of their circumferences​

Answer 1

area ratio directly proportional to r^2 while circumference is directly proportional to r

so ratio of....= rt400=20

Answer 2

Given:

πR^{2} = 400πr^{2}

R^(2)= 400r^(2)

R = 20r  .........(eq.1)_

Therefore circumference=

2πR/2πr = 2π20r/2πr

⇒ 20r/r = 20:1

therefore the ratio is 20:1