So this is complicated, but to get a general idea simple we use common sense and say its bigger than 4, since its length is bigger than the supposed 4 length. So then we get the options 6, 5, and 24. Now we can do some basic math and figure that the circle radius is around 4 so its probably 6 or 5. Slim change of 24.
People who did the physical math can check it with my answer.
