By using the area of the ring we will see that the radius of the inner circle is 3cm.
What is the radius of the inner circle?
I assume that we have some kind of ring. To get the area of the ring, we need to take the area of the circle defined by the outer radius of the ring, and subtract the area defined by the circle with the inner radius of the ring.
Remember that the area of a circle of radius R is:
A = pi*R^2
We know that:
The radius of the outer circle is 5cm, so its area is:
A = pi*(5cm)^2 = pi*25cm^2
And the area of the ring is pi*16 cm^2
Then the area of the inner circle should be such that:
pi*25cm^2 - A' = pi*16cm^2
Then, solving for A'
A' = pi*25cm^2 - pi*16cm^2 = pi*9cm^2 = pi*(3cm)^2
So the radius of the inner circle is 3cm.
If you want to learn more about circles, you can read:
https://brainly.com/question/1559324
