Respuesta :

Answer:

r=3

Step-by-step explanation:

  • The equation of a circumference is [tex](x-a)^2+(y-b)^2=r^2[/tex].
  • Then , in this case [tex]r^2=9[/tex], and then to know the value of r we just simply have to calculate the square root of 9, which is 3.