Question

if area of circle decreases from 25 π to 9π , the ratio of circumference from the first circle to the second is??

Answer 1

Answer:

5 : 3

Step-by-step explanation:

area of 1st circle πr^2 = 25π

$\pi {r}^{2} = 25\pi \\ {r}^{2} = 25 \\ r = \sqrt{25} = 5 \\ circumference \: of \: circle \: 2\pi r \\ 2 \times 5 \times \pi = 10\pi$

area of 2nd circle πr^2

$\pi {r}^{2} = 9\pi \\ {r}^{2} = 9 \\ r = \sqrt{9} = 3 \\ circumference \: of \: circle \: 2\pi r = 2 \times 3 \times \pi \\ 6\pi$

ratio of the circumference is

10π : 6π

5 : 3