Question

if two circles have circumference of 12 pi inches and 18 pi inches,find the ratio between their radii

Answer 1

The formula for the circumference is:

`2\pi r`
So to find first radius:

`2\pi r = 12\pi \\ \\ \pi r = 6\pi \\ \\ r = 6`
Second radius:

`2\pi r = 18\pi \\ \\ \pi r = 9\pi \\ \\ r = 9`
The ratio between them is:

`(6)/(9) = (2)/(3) = 0.66667`