Respuesta :

Answer:r≈12.99

Step-by-step explanation:

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