Answer:65
Step-by-step explanation:
The answer in simplest form is 1/4.
Solution: We are given below data:

Now to find the mean deviation, we use the below formula:

Where:
represents the summation
X, represents the observation.
represents the mean
N represents the number of observation.


Therefore, the mean deviation is:

= 4
Using the Pythagorean theorem we can solve for the radius
see attached picture: