Question 483783
Distance between ywo points (x1,y1) & (x2,y2)
is  given by the formula

{{{d= sqrt((x1-x2)^2+(y1-y2)^2)}}}

plug the values

{{{d= sqrt((-3-9)^2+(-1-4)^2)}}}

{{{d=sqrt((-12)^2+(-5)^2)}}}

{{{d= sqrt((144+25))}}}

{{{d=sqrt(169)}}}

d=13
so you know the radius now.

m.ananth@hotmail.ca