Posted by Jessi on .
How are the radii of 2 two concentric circles related to the distance between them?
I tried making an equation using their cirmcumferences but I was way off. All I did was subtract the inner circle's circumference from the outer circle's circumference and set it equal to the distance between them and I know that would never work

geometry 
Reiny,
Not too sure if I understand the question correctly"the distance between them" ?
who is the "them", the circles ?
e.g. radius of first circle = 8
radius of second circle = 3
difference between them is 5
So the distance between them is the difference of the two radii.