Question 564250
To find the radius you need a point along the circle and the center. The center is (3,5) the point along the circle is the origin (0,0)

We can use distance formula to solve from here, and the zeros will make this easy
{{{d=sqrt((3-0)^2+(5-0)^2)}}}
{{{d=sqrt(9+25)}}}
{{{d=sqrt(34)}}}