First of all, it is 2r

and it would be divide by 3.14 (pi) and then you should have the diameter. Then divide by 2 to find radius.
The experiment with the least number of trials.
Experimental probability is more accurate and more close to theoretical probability by having the most trials. More trials = more accuracy. Less trials = less accuracy.
36/27=1.3
7x1.3=9.1
The actual length is 9.1meters