Question 426478
Answer: The standard equation of the circle centered at (h,k) is given:

   {{{(x-h)^2+(y-k)^2=r^2}}} where r is the radius and (h,k) the center.

 If the center is the origin then the equation will be:

     {{{x^2+y^2=r^2}}} where r is the radius.

 If a line pas through the points (X1,Y1) and (X2,Y2),its equation is:

     {{{(Y-Y1)/(Y2-Y1)=(X-X1)/(X2-X1)}}}

Where: m=(Y2-Y1)/(X2-X1) is the slope of the line.