Given that circumfernce of the circle = 81.64 meters
Now question says to find the radius of the given circle.
We can use the formula of the circumference of the circle. Which is given by:
Circumference = 2 \pi r
where "r" represents radius of the circle and , pi = 3.14
Plug the given values
81.64 = 2* 3.14* r
81.64 = 6.28 r

13 = r
Hence radius of the given circle is 13 meters.