Question 753011
L: 3x+y+1=0 and P: (-1,-3)

The perpendicular distance from L to P is to be the radius:


{{{
r^2=d^2=(ax[1]+by[1]+c)^2/(a^2+b^2)=(3*(-1)+1(-3)+1)^2/((-1)^2+(-3)^2)=5/2
}}}


From the equation of a circle:


{{{
(x+1)^2+(y+3)^2=5/2
}}}


:)