1.8
to find the circumference of a circle you have to multiple the diameter by pi (3.14). so if you have the circumference already just switch around the equation (since you don’t know the diameter) to 10.99 divided by 3.14 to find the diameter and you get 3.5. but thats the diameter and you have to find the radius so divide 3.5 by two and you get 1.75 and 1.75 rounded to the nearest tenths is 1.8