Answer:
3 cm
Step-by-step explanation:
So the area of the total circle is:
[tex]\pi \times 5^{2} = \pi \times 25[/tex]
If you remove the outer band you have the area of the inner circle
[tex]25\pi - 16\pi = 9\pi[/tex]
This means that the inner circle had an area of
area = pi * r^2
9 pi = pi * r^2
r =
[tex] \sqrt{9} = 3[/tex]
So the radius of the inner circle is 3.
