Answer:
r = [tex]3\sqrt{2}[/tex]
Step-by-step explanation:
equation of a circle: [tex](x-a)^2+(y-b)^2=r^2[/tex]
where (a, b) is the center and r is the radius
Therefore, for the equation [tex]x^2+y^2=18[/tex]
⇒ r = [tex]\sqrt{18}[/tex] = [tex]3\sqrt{2}[/tex]
