If circumference of circle R is 12 times pi is and circumference of circle S is 32 times pi , which is the ratio of a radius of S to a radius of R?

Question

If circumference of circle R is 12 times pi is  and circumference of circle S is 32 times pi  , which is the ratio of a radius of S to a radius of R?

anonymous · Answer

what is the formula for the circumference of a circle?

anonymous · Answer

got the answer eh?

anonymous · Answer

2*pi*r.

anonymous · Answer

okay. what is the radius of circle R then?

anonymous · Answer

it doesnt say

anonymous · Answer

you know the formula for the circumference right?
you know the actual circumference of the circle.
equate them
in other words,
2 pi r = 12 pi
so r = ?

anonymous · Answer

1.91

anonymous · Answer

how did you get that? show me the steps.

anonymous · Answer

i did 2 times pi which gave me 6.28 then i divided that by 12

anonymous · Answer

it is not just 12, it is 12 times pi. so you have to divide 12 times pi by 2 times pi.

anonymous · Answer

ok i got 59.2

anonymous · Answer

how?

anonymous · Answer

i did 12 times pi and 2 times pi and then divided them

anonymous · Answer

$$r = \frac{12 \times \pi}{2 \times \pi} = ?$$

anonymous · Answer

no i got 5.98

anonymous · Answer

okay. you should actually get 6.
2 goes in 12  6 times. and the pi on the numerator cancels out the pi on the denominator.
so the radius is 6.

anonymous · Answer

similarly find out the radius for circle S

anonymous · Answer

i got it thnks

anonymous · Answer

great.